Ambulatory medical apparatus with hand held communication device

ABSTRACT

A communication device (CD) exchanges messages with an implantable infusion pump via telemetry such that commands are supplied thereto and operational information is obtained therefrom. The CD is controlled, at least in part, by a processor IC according to a software program operating therein and provides feedback to a user via a visual display, an audio alarm, and a vibrational alarm, and allows input from the user via a touch sensitive keypad. Certain input functions are restricted by password. The visual display includes an icon and fixed element display region and a bitmap display region. The fixed element display region includes time and date displays, battery and drug level displays that decrement, and a moving delivery state display. Various screens allow operational or log information to be displayed and/or user entry of commands. Program features when disabled are removed from a series of screen options that can be scrolled through.

RELATED APPLICATIONS

This application is a continuation of Ser. No. 09/768,196, filed Jan.22, 2001, which claims the benefit of U.S. Provisional PatentApplication No. 60/177,414, filed Jan. 21, 2000, the entire content ofeach of which is incorporated herein by reference.

FIELD OF THE DISCLOSURE

This invention relates generally to electronically controlled ambulatorymedical systems that include an ambulatory medical device and a handheld microprocessor controlled communication device with enhanced userfriendliness including enhanced display/patient notification features,safety features, and/or medical device programming/communicationfeatures. Preferred embodiments relate to implantable infusion pumps andexternal devices for communicating therewith.

BACKGROUND

Implantable infusion pumps for dispensing controlled volumes of a drug(e.g. insulin) have been proposed and even attempts at implementationand commercialization made.

One such pump is the MMT2001 Implantable Pump System as sold by MinimedInc. of Northridge, Calif. This device presented the user with theability to perform basic infusion actions such as the delivery of abasal rate, delivery of a temporary basal rate, or the delivery of ameal bolus. The user was, however, not presented with the ability toperform more sophisticated delivery related operations that may bedesirable for optimum control of blood glucose level. When using thissystem three delivery options exist: (1) delivery of a standard butprogrammable basal rate, (2) delivery of a standard basal rate and ameal bolus simultaneously, or (3) delivery of a temporary basal rateeither immediately or at a programmable start time within a specifiablestart time. In this system not only could a meal bolus and a temporarybasal rate not occur at the same time, they could not be programmed intothe system when the other was already programmed but delivery not yetcompleted even though no overlap in delivery between the two amountsmight exist. As such the user could only program one variable rate intothe system at a time, even in the event that several variable rates maybe desired to follow one another. As such, this system is less thanoptimal with regard to user convenience in programming his/her insulintreatment.

The system also suffered from an external controller that was large,hard to carry and awkward to use. The controller dimensions are 6.0inches by 3.5 inches by 1.3 inches with a display that is a smallfraction of the size of the face of the controller. The controllerincluded a cover plate that would close over the display area when notin use and would be opened during use. More particularly, duringprogramming the cover plate is opened at a ninety-degree angle relativeto the front of the display to allow viewing of the display and to allowpositioning of the cover plate immediately over the site of the infusionpump so that successful telemetry communication may occur. As such thesystem does not supply delivery or system status related information tothe user accept at the times that the user elects to open and turn onhis/her controller.

The system further suffers from the inability of the implantable deviceto send out unsolicited telemetry messages to the controller concerningoperational conditions within the implantable device. As such, systemconditions within the implantable device (other than communicationrelated failures) are primarily conveyed to the user via an auditoryalarm that is internal to the implantable device.

The system further suffers from the entire operational history of thepump being subject to loss as this historical data is only held in thecontroller.

The system further suffered from a relatively short life for theimplantable device of approximately 2.5 years.

Based on the above noted shortcomings, and other shortcomings of systemsin the field, a need exists for improved systems that offer enhancedprogramming capabilities, enhanced user interface capabilities, reducedcontroller size, enhanced operational performance, enhanced security ofsystem/patient historical data, enhanced safety features, and/orenhanced implantable device life.

It is believed that related shortcoming may exist in other ambulatorymedical devices as well, such as in externally carried infusion pumps,implantable pacemakers, implantable defibrillators, implantable neuralstimulators, implantable physiological sensors, externally carriedphysiologic sensors, and the like.

SUMMARY OF THE INVENTION

It is a first object of certain aspects of the invention to enhanceprogramming capabilities for ambulatory medical systems and inparticular for implantable infusion pump systems.

It is a second object of certain aspects of the invention to enhanceuser interface capabilities in ambulatory medical systems and inparticular for implantable infusion pump systems.

It is a third object of certain aspects of the invention to reducesystem size for patient convenience in ambulatory medical systems and inparticular for implantable infusion pump systems.

It is a fourth object of certain aspects of the invention to enhanceoperational performance of ambulatory medical systems and in particularfor implantable infusion pump systems.

It is a fifth object of certain aspects of the invention to enhancesecurity of system/patient historical data.

It is a sixth object of certain aspects of the invention to enhance theoperational safety of ambulatory medical systems and in particular ofimplantable infusion pump systems.

It is a seventh object of certain aspects of the invention to enhancelongevity of ambulatory medical systems and in particular of implantableinfusion pump systems.

Other objects and advantages of various aspects of the invention will beapparent to those of skill in the art upon review of the teachingsherein. The various aspects of the invention set forth below as well asother aspects of the invention not specifically set forth below butascertained from the teachings found herein, may address the above notedobjects or other objects ascertained from the teachings hereinindividually or in various combinations. As such, it is intended thateach aspect of the invention address at least one of the above notedobjects or address some other object that will be apparent to one ofskill in the art from a review of the teachings herein. It is notintended that all, or even a portion of these objects, necessarily beaddressed by any single aspect of the invention even though that may bethe case with regard to some aspects.

A first aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system, wherein the communication device weighs no more thanabout 10 oz and includes a CD housing having a volumetric size smallerthan 20 cubic inches.

A second aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system, wherein the communication device additionally includesa CD readable display which includes a bit map region for displayingselected information.

A third aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system wherein the communication device additionally includesa readable display which includes at least one icon.

A fourth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system wherein the communication device additionally includesa readable CD display which further includes a backlight.

In a specific variation of the fourth aspect of the invention thecommunication device additionally includes a touch sensitive CD inputdevice and wherein the backlight is automatically activated when one ormore selected locations on the CD input device are touched.

In a specific variation of the fourth aspect of the invention thebacklight is activated automatically when a light level falling on asensor on the communication device is less than a predetermined amountand a touch sensitive region of the communication device is touched.

A fifth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system, wherein the communication device further includes anautomatically activated CD alarm that is capable of providing a signalto the patient of the existence of a particular condition in at leastone of the medical device or the communication device, and wherein theCD alarm includes at least one of a CD vibration mechanism or a CD audioalarm mechanism.

In a specific variation of the fifth aspect of the invention thecommunication device is configured to enable a patient to select betweenthe CD alarm using the audio and vibration mechanism.

In a specific variation of the fifth aspect of the invention an alarmcondition in the medical device is transmitted to the communicationdevice via an unsolicited telemetry message.

In a specific variation of the fifth aspect of the invention thecommunication device is configured to automatically switch from one ofthe audio alarm or the vibration alarm to the other of the vibrationalarm or the audio alarm under selected circumstances associated with atleast one error condition.

In a specific variation of the fifth aspect of the invention one of themedical device or the communication device includes an audio alarm thatproduces a plurality of tones emitted in a predetermined sequence.

A sixth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system wherein the communication device additionally includesa CD touch sensitive input device, and wherein the communication deviceadditionally includes a readable CD display which further includes acapability of displaying different colors.

In a specific variation of the sixth aspect of the invention the CDdisplay is configured to display a single color at any one time.

In a specific variation of the sixth aspect of the invention the CDdisplay is configured to display a plurality of colors at a single time.

A seventh aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication deviceadditionally includes a readable display that is also touch sensitivefor allowing user inputs to be entered into the communication device.

A eighth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system, wherein the communication device additionally includesa CD touch sensitive input device and a CD speaker that is controlled tosupply speech based output to the patient.

A ninth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system, wherein the communication device additionally includesa CD input device which further includes a CD microphone and a CD voicerecognition system that are controlled to allow speech based input tothe communication device.

A tenth aspect of the invention provides a medical system that includes(a) an ambulatory medical device (MD) that includes MD electroniccontrol circuitry that further includes at least one MD telemetry systemand at least one MD processor that controls, at least in part, operationof the MD telemetry system and operation of the medical device, whereinthe medical device is configured to provide a treatment to a body of apatient or to monitor a selected state of the body; and (b) acommunication device (CD) that includes CD electronic control circuitrythat further includes at least one CD telemetry system and at least oneCD processor that controls, at least in part, operation of the CDtelemetry system and operation of the communication device, wherein theCD telemetry system sends messages to or receives messages from the MDtelemetry system wherein the communication device additionally includesa CD touch sensitive input device, and wherein the communication deviceis configured to perform a plurality of functions, and wherein theperformance of at least a first function requires that the communicationdevice be placed in an operational state dictated by a first or a secondpassword and the performance of at least a second function requires thatthe communication device be placed in an operational state dictated thesecond password.

In a specific variation of the tenth aspect of the invention thecommunication device can perform all functions with the second passwordthat can be performed with the first password.

A eleventh aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device includesa touch sensitive CD input device, and wherein at least one of thecommunication device or the medical device may be reset, or placed in astate to allow reset to occur, by contacting a plurality of selectedlocations on the touch sensitive CD input device in a prescribed order.

In a specific variation of the eleventh aspect of the invention passwordmust be entered into the communication device prior to touching theplurality of selected locations on the touch sensitive CD input devicein order for reset to occur.

In a specific variation of the eleventh aspect of the invention apassword must be entered into the communication device after touchingthe plurality of selected locations on the touch sensitive CD inputdevice in order for reset to occur.

In a specific variation of the eleventh aspect of the invention theplurality of touch sensitive locations are touched sequentially in orderfor reset to occur.

In a specific variation of the eleventh aspect of the invention at leasta portion of the plurality of touch sensitive locations must be touchedsimultaneously for reset to occur.

In a specific variation of the eleventh aspect of the invention at leasta portion of the plurality of touch sensitive locations must be touchedand then untouched in a particular order for reset to occur.

In a specific variation of the eleventh aspect of the inventionresetting may occur to different extents depending on variations in theplurality of touch sensitive locations touched, variations in thesequence of touching, or variations in the sequence of untouching.

A twelfth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device isconfigured to receive status information on an MD battery via telemetryfrom the medical device.

In a specific variation of the twelfth aspect of the invention themedical device provides a periodic indication of the MD battery voltagewhen the MD battery is experiencing a current load that is closer to theminimum load during normal operation of the medical device than amaximum load during normal operation.

In a specific variation of the twelfth aspect of the invention themedical device provides a periodic indication of the MD battery voltagewhen the MD battery is experiencing a current load which is closer tothe maximum load during normal operation than a minimum load duringnormal operation.

In a specific variation of the twelfth aspect of the invention MDbattery status is provided using both a lower current load and a highercurrent load at least once a week.

In a specific variation of the twelfth aspect of the invention thecommunication device provides an auditory, visual, or tactile warningwhen the MD battery is estimated to be capable of powering the medicaldevice for less than a predetermined additional amount of time.

A thirteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication deviceadditionally includes at least one battery and the medical deviceincludes at least one battery, and wherein the communication device isconfigured to display log data of MD battery status information or CDbattery status information.

In a specific variation of the thirteenth aspect of the invention thelog information includes a plurality of voltage readings taken from apredefined battery when the predefined battery is powering a first loadand when the predefined battery is powering a second load which isdifferent from the first load.

In a specific variation of the thirteenth aspect of the invention thelog data is accumulated at least once per week.

A fourteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication deviceadditionally includes a socket for a removable memory module.

In a specific variation of the fourteenth aspect of the invention thecommunication device includes the removable memory module.

In a specific variation of the fourteenth aspect of the invention theremoval memory module contains replacement software for thecommunication device, replacement software for the medical device, orcalibration data for a sensor that forms part of the medical device.

A fifteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical device includes animplantable device, and wherein the communication device includes amemory for simultaneously storing a plurality of parameters that areeach used during a different time period to, at least in part, controlthe treatment provided to the body or the monitoring of the body that isprovided by the medical device.

In a specific variation of the fifteenth aspect of the invention theimplantable device includes an infusion pump that is capable ofdispensing a selected quantity of a drug according to a programmedparameter, and wherein each of the plurality of parameters includes abasal rate parameter that is programmed for use in controlling thedispensing of the drug during a selected time period during the day. Ina further variation the plurality of parameters comprise a plurality ofsets of parameters, wherein each set includes a plurality of parameters,wherein the medical device is capable of storing only one set at a time,and wherein the communication device transmits a selected on of the setsto the communication device when it is desired for the parameters of thetransmitted set to control, at least in part, the dispensing of thedrug.

A sixteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical system additionallyincludes a second device (SD) that includes an SD communication system,wherein the communication device further includes a second CDcommunication system, and wherein the communication device isprogrammable so as to echo all CD telemetry system messages, sent orreceived from the medical device, through the second CD communicationsystem to the SD communication system.

A seventeenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical system additionallyincludes a second device (SD) that includes an SD communication system,wherein the communication device further includes a second CDcommunication system, and wherein the communication device isprogrammable to pass messages received from the second device on to themedical device via transfer from the SD communication system to thesecond CD communication system to the CD telemetry system and on to MDtelemetry system of the medical device, and/or to pass messages receivedfrom the medical device to the second device via transfer from MDtelemetry system to the CD telemetry system to the second CDcommunication system and then onto the SD telemetry system of the seconddevice, and wherein the content of the messages is passed withoutmodification.

A eighteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical system additionallyincludes a second device (SD) that includes an SD communication system,wherein the communication device further includes a second CDcommunication system that is capable of sending messages to or receivingmessages from the SD communication system, and wherein the communicationdevice additionally includes a CD keypad, and wherein the communicationdevice is capable of receiving messages from the second device thatemulate keystrokes on the keypad.

A nineteenth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device isprogrammed to accept input parameters that specify the delivery of apredefined quantity of treatment to the body of the patient over aprescribed time period wherein the average rate of delivery per minuteof portions of the predefined quantity varies as a function of timeaccording to a preprogrammed delivery profile.

In a specific variation of the nineteenth aspect of the invention thepreprogrammed delivery profile results in a bell shaped curve of averagedelivery per minute versus time. In a further variation thecommunication device allows the patient to select a most suitable of aplurality of bell shaped delivery profiles. In a further variation atleast one of the curves is symmetric. In still a further variation atleast one of the curves is non-symmetric with a generally steeper upwardslope than downward slope.

A twentieth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device ispowered by a replaceable battery and wherein sufficient power is storedin one or more capacitors within the communication device that acontrolled power down can occur when the replaceable battery is removedsuch that upon replacement of the battery the communication device neednot be reprogrammed to resume operation.

In a specific variation of the twentieth aspect of the invention thecommunication device monitors the voltage on the replaceable batter soas to detect a removal of the battery and initiate and complete acontrolled shut down prior to the capacitors losing a required minimumvoltage.

A twenty-first aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical device is configuredto provide a drug to the body of a patient in amounts that are integermultiples of a quantized amount, wherein the communication device isprogrammed to allow entry of delivery quantities that are not integralmultiples of the quantized amount.

A twenty-second aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication deviceadditionally includes a CD display device for providing visualcommunication signals to the patient which further includes a zoomabledisplay so that the size of displayed images may be adjusted to adesired size.

In a specific variation of the twenty-second aspect of the invention theCD display device includes a LCD bit map display.

A twenty-third aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical device includes aninfusion pump, and wherein the CD display device is controlled to show aplurality of infusion parameters simultaneously.

A twenty-fourth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the CD display device includes amoving image that graphically depicts a status of the system.

In a specific variation of the twenty-fourth aspect of the invention themedical device includes an infusion pump and the status being depictedincludes an indication of a delivery status. In a further variation themoving image rotates. In a further variation the image includes a numberof elements that may be active or inactive and differing numbers ofactive elements indicates different delivery states.

A twenty-fifth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device includesa CD display controlled by the at least one CD processor for providingvisual feedback to the patient, and wherein the feedback includes adisplay of the quantity of a consumable estimated to be remaining in thesystem.

In a specific variation of the twenty-fifth aspect of the invention theconsumable is a quantity of a drug estimated to be remaining in areservoir.

In a specific variation of the twenty-fifth aspect of the invention theconsumable is either (1) battery power remaining in a replaceable CDbattery in the communication device and a voltage level on the CDbattery is graphically depicted with a desired resolution, or (2)battery power remaining in an MD battery in the medical device and avoltage level on the battery is graphically depicted with a desiredresolution.

A twenty-sixth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the CD display is controlled todepict a plurality of patient programmable options and wherein at leastone of the patient programmable options may be enabled or disabled suchthat when disabled the at least one patient programmable option is nolonger displayed as an option.

A twenty-seventh aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the medical device or thecommunication device monitors battery voltage and generates a voltagelog, wherein the medical device monitors a CD voltage of a CD battery inthe communication device and generates a CD voltage log.

In a specific variation of the twenty-seventh aspect of the inventionthe log includes a plurality of CD voltage values for each of aplurality of different current drain states.

A twenty-eighth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein both the medical device and thecommunication device have memories for storing selected data aboutsystem operation, wherein at least a portion of the selected data isduplicated in the medical device and the communication device.

In a specific variation of the twenty-eighth aspect of the invention thecommunication device is programmed to periodically synchronize theduplicated data.

In a specific variation of the twenty-eighth aspect of the invention atleast a portion of the selected data is synchronized automatically or issynchronized in response to a synchronization command.

A twenty-ninth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device isprogrammed to allow a user to set a plurality of parameters topredefined default values by issuing a command that does requirespecification of any of the default values.

A thirtieth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device iscapable of performing a test of battery voltage with a load on thebattery.

In a specific variation of the thirtieth aspect of the invention thetest of battery voltage is performed automatically and periodically. Ina further variation at least one of the following will occur, (1) thebattery voltage is also automatically and periodically checked with thebattery under a minimal load, (2) at least one selected electricalcomponent is forced on to produce the load for testing, or (3) the testis made to occur at least in part when at least one selected electricalcomponent is powered on in the performance of its normal operation,wherein the electrical component provides a load for the testing.

A thirty-first aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein at least one of the medical deviceor communication device has a memory for storing at least onecalibration factor needed for proper operation of the system.

In a specific variation of the thirty-first aspect of the invention themedical device includes an infusion pump mechanism for dispensing a drugheld in a reservoir within the medical device and the at least onecalibration factor includes at least one of (1) information about theconcentration of the drug, (2) delivery volume per discrete operation ofan infusion pump mechanism, (3) the amount of drug placed in thereservoir when filled, (4) a voltage value necessary to cause the pumpmechanism to operate properly, (5) a value to be used by a pulse stealercircuit, (6) a calibration factor to be used by an analog to digitalconverter, or (7) a specific telemetry ID of the device.

A thirty-second aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein at least one of the medical deviceor communication device includes a first component or module that may bepowered directly by a battery when the battery's output voltage is abovea predetermined level, and wherein the at least on of the medical deviceor communication device includes a voltage up converter that is used tosupply electrical potential to the first component or module when thebattery voltage is below the predetermined level.

A thirty-third aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein at least one watchdog circuit iscapable of causing the CD processor to undergo a predefined process inthe event that the watchdog circuit does not receive a first signal anda second signal, which is different from the first signal, within apredefined time period.

In a specific variation of the thirty-third aspect of the invention thepredefined process causes the CD processor to be reset. In a furthervariation one of the first or second signals is a signal generated bymainline software. In a further variation the other of the first orsecond signals is a signal generated by interrupt hardware.

A thirty-fourth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein an antenna for the MD telemetrysystem is mounted on a hybrid circuit board in the medical device andwherein the antenna for the CD telemetry system is mounted on a hybridcircuit board in the communication device.

A thirty-fifth aspect of the invention provides a medical system thatincludes (a) an ambulatory medical device (MD) that includes MDelectronic control circuitry that further includes at least one MDtelemetry system and at least one MD processor that controls, at leastin part, operation of the MD telemetry system and operation of themedical device, wherein the medical device is configured to provide atreatment to a body of a patient or to monitor a selected state of thebody; and (b) a communication device (CD) that includes CD electroniccontrol circuitry that further includes at least one CD telemetry systemand at least one CD processor that controls, at least in part, operationof the CD telemetry system and operation of the communication device,wherein the CD telemetry system sends messages to or receives messagesfrom the MD telemetry system, wherein the communication device monitorselectrical activity of at least one electronic module or componentlocated within the communication device and compares the electricalactivity to at least one predetermined value.

In a specific variation of the thirty-fifth aspect of the invention,there will be one of the following, (1) the at least one electronicmodule is located within an application specific integrated circuit thatincludes the CD processor, (2) the at least one electronic moduleincludes a crystal oscillator circuit, (3) the at least one electronicmodule includes a driver for the treatment or monitoring device, (4) thepredetermined value includes an upper and lower limit of a range ofvalues, or (5) the electrical activity includes a current flow.

Additional specific variations, provide the medical devices of each ofthe above aspects and above noted variations as implantable devices suchas implantable infusion pumps, implantable physiological sensors,implantable stimulators, and the like, or external devices suchsubcutaneous delivery infusion pumps or sensors that ascertain aphysiological parameter or parameters from subcutaneous tissue or fromthe skin of the patient. Such infusion pumps may dispense insulin,analgesics, neurological drugs, drugs for treating aids, drugs fortreating chronic ailments or acute ailments. Sensors may be used todetect various physiological parameters such as hormone levels, insulin,pH, oxygen, other blood chemical constituent levels, and the like. Thesensor may be of the electrochemical type, optical type, and may or maynot be enzymatic in operation.

In even further variations of the above noted aspects, and above notedvariations, one or more of the following is provided: (1) a firstportion of the MD telemetry system is incorporated into the MD processorand a second portion of the MD telemetry system is external to the MDprocessor, (2) a first portion of the CD telemetry system isincorporated into the CD processor and a second portion of the CDtelemetry system is external to the CD processor, (3) the MD processorincludes an MD central processing unit and at least one other MDfunctional module, (4) the CD processor includes a CD central processingunit and at least one other CD functional module, (5) the MD electroniccontrol circuitry includes at least one external MD functional module,other than a portion of the MD telemetry system, that is external to theMD processor, or (6) the CD electronic control circuitry includes atleast one external CD functional module, other than a portion of the CDtelemetry system, that is external to the CD processor.

Still additional aspects of the invention set forth method counterpartsto the above system aspects as well as to other functional associationsand relationships, and processes that have not been specifically setforth above but will be understood by those of skill in the art from areview of the teachings provided herein.

Further aspects of the invention will be understood by those of skill inthe art upon reviewing the teachings herein. These other aspects of theinvention may provide various combinations of the aspects presentedabove as well as provide other configurations, structures, functionalrelationships, and processes that have not been specifically set forthabove.

BRIEF DESCRIPTION OF THE DRAWINGS

The above referred to objects and aspects of the present invention willbe further understood from a review of the description to follow, thedrawings, and the claims set forth hereafter, wherein:

FIG. 1 a depicts a perspective view of the main body of the implantabledevice of the first preferred embodiment;

FIG. 1 b depicts a perspective view of the support and catheter assemblythat attaches to the main body of the implantable device of the firstpreferred embodiment;

FIG. 2 depicts a perspective view of the external communication deviceof the first preferred embodiment; and

FIG. 3 depicts a block diagram of the main components/modules of boththe implantable device and the external communication device of thefirst preferred embodiment.

FIGS. 4 a and 4 b depict a block diagram of the main components/modulesand their inter-connections as used in the external communication deviceof the first preferred embodiment;

FIG. 5 depicts the display screen of the external communication deviceof the first preferred embodiment;

FIG. 6 depicts a block diagram of the various modules of the processorIC used in both the implantable device and the external communicationdevice of the first preferred embodiment;

FIGS. 7 a and 7 b depicts the main menu structure for the user interfaceof the external communication device of the first preferred embodiment;

FIGS. 8 a and 8 b depicts the setup menu structure for the userinterface of the external communication device of the first preferredembodiment;

FIGS. 9 a and 9 b depicts the setup ii menu structure for the userinterface of the external communication device of the first preferredembodiment;

FIGS. 10 a and 10 b depicts the supervisor menu structure for the userinterface of the external communication device of the first preferredembodiment;

FIG. 11 depicts the bolus delivery sequence or menu structure for theuser interface of the external communication device of the firstpreferred embodiment; and

FIG. 12 depicts the communication sequence associated with the userinterface of the external communication device of the first preferredembodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Various details about the structural and functional configuration andoperation of preferred ambulatory medical devices and preferredcommunication devices are found in several US patent applications filedconcurrently herewith and incorporated herein by reference in theirentireties: (1) Docket No. USP-1075-A, (2) Docket No. USP-1076-A, (3)Docket No. USP-1077-A, (4) Docket No. USP-1079-A, and (5) Docket No.USP-1080-A.

U.S. patent application Ser. No. To Be Determined, filed on Jan. 22,2001 (concurrently herewith), by Starkweather, et al., entitled“Ambulatory Medical Apparatus and Method Having Telemetry ModifiableControl Software”, corresponding to Medical Research Group, Inc. DocketNo. USP-1075-A, is hereby incorporated herein by this reference as ifset forth in full herein. This application provides teachings concerningan implantable medical device (e.g. infusion pump) and handheldcommunication device wherein the implantable device is capable ofoperating under control of different software programs, wherein a firstprogram operates after resetting the implantable device and is notcapable of allowing significant medical functionality but is capable ofselected telemetry operations including telemetry operations that allowreplacement software to be downloaded, and wherein a second program maybe caused to take control of the device and enables medicalfunctionality and selected telemetry operations but is incapable ofreceiving replacement software. It is also taught that a software imagemay be received in multiple messages where each message is provided withits own validation code and wherein a validation code for the wholeimage is provided and wherein each provided validation code mustcompared to a derived validation code prior to accepting the validity ofthe replacement software.

U.S. patent application Ser. No. To Be Determined, filed on Jan. 22,2001 (concurrently herewith), by Lebel, et al., entitled “AmbulatoryMedical Apparatus and Method Using a Robust Communication Protocol”,corresponding to Medical Research Group, Inc. Docket No. USP-1076-A, ishereby incorporated herein by the references as if set forth in fullherein. An implanted medical device (e.g. infusion pump) and externaldevice communicate with one another via telemetry wherein messages aretransmitted under a robust communication protocol. The communicationprotocol gives enhanced assurance concerning the integrity of messagesthat impact medical operations of the implantable device. Messages aretransmitted using a multipart format that includes a preamble, a framesync, a telemetry ID, data, and a validation code. The data portion ofthe message includes an op-code that dictates various other elementsthat form part of the message. The data portion may also includeadditional elements such as sequence numbers, bolus numbers, andduplicate data elements. A telemetry ID for the transmitting device maybe implicitly embedded in the message as part of the validation codethat is sent with the message and that must be pre-known by the receiverto confirm the integrity of the received message.

U.S. Patent Application Serial No. To Be Determined, filed on Jan. 22,2001 (concurrently herewith), by Bowman, et al., entitled “AmbulatoryMedical Apparatus and Method using a Telemetry System with PredefinedReception Listening Periods”, corresponding to Medical Research Group,Inc. Docket No. USP-1077-A, is hereby incorporated herein by thereference as if set forth in full herein. This application providesteachings concerning an implantable medical device (e.g. infusion pump)and an external device that communicate with one another via telemetrymessages that are receivable only during listening windows. Eachlistening window is open for a prescribed listening period and is spacedfrom other listening windows by an interval. The listening period istypically kept small to minimize power consumption. To increaselikelihood of successful communication, the window may be forced to anopen state, by use of an attention signal, in anticipation of anincoming message. To further minimize power consumption, it is desirableto minimize use of extended attention signals, and this is accomplishedby the transmitter maintaining an estimate of prescribed listening starttimes and attempting to send messages only during listening periods. Inthe communication device, the estimate is updated as a result ofinformation obtained with the reception of each message from the medicaldevice.

U.S. patent application Ser. No. To Be Determined, filed on Jan. 22,2001 (concurrently herewith), by Starkweather, et al., entitled “Methodand Apparatus for Communicating Between an Ambulatory Medical Device andControl Device Via Telemetry Using Randomized Data”, corresponding toMedical Research Group, Inc. Docket No. USP-1079-A, is herebyincorporated herein by this reference as if set forth in full herein.This application provides teachings concerning an implantable medicaldevice (e.g. infusion pump) and handheld communication device thatcommunicate with one another via telemetry wherein transmitted messageshave enhanced numbers of and/or regularity of bit transitions tominimize the risk of synchronization loss between transmitted bits ofdata and received bits of data. It is taught that bit transitions forportions of messages may be enhanced by applying a pseudo-randomizationscheme to those portions of messages that are transmitted in a way thatallows the receiver to extract the original data from the receivedrandomized data. Preferred randomization techniques modify (i.e.randomize) the data using a CRC value that is being accumulated whilesimultaneously causing the modified data to modify subsequentaccumulation of the CRC itself. Upon reception, the reversal of datarandomization is then made to occur so that the intended message isappropriately received.

U.S. patent application Ser. No. To Be Determined, filed on Jan. 22,2001 (concurrently herewith), by Lebel, et al., entitled “MicroprocessorControlled Ambulatory Medical Apparatus with Hand Held CommunicationDevice”, corresponding to Medical Research Group, Inc. Docket No.USP-1080-A, is hereby incorporated herein by this reference as if setforth in full herein. This application provides teachings concerning animplantable medical device (e.g. infusion pump) and handheldcommunication device wherein an implantable infusion pump possessesoperational functionality that is, at least in part, controlled bysoftware operating in two processor ICs which are configured to performsome different and some duplicate functions. The pump exchanges messageswith the external communication device via telemetry. Each processorcontrols a different part of the drug infusion mechanism such that bothprocessors must agree on the appropriateness of drug delivery forinfusion to occur. Delivery accumulators are incremented and decrementedwith delivery requests and with deliveries made. When accumulatedamounts reach or exceed, quantized deliverable amounts, infusion is madeto occur. The accumulators are capable of being incremented by two ormore independent types of delivery requests. Operational modes of theinfusion device are changed automatically in view of various systemerrors that are trapped, various system alarm conditions that aredetected, and when excess periods of time lapse between pump andexternal device interactions.

The first embodiment of the present invention provides a long termimplantable medical delivery system that controllably supplies insulinto the body of a patient afflicted with diabetes mellitus. Thisembodiment includes an implantable medical device and an externalcommunication device. In the most preferred embodiments, thecommunication device is a hand held device that is used directly by thepatient to interact with the medical device as opposed to being limitedto use by a physician, nurse, or technician. It is preferred that thecommunication device provide (1) the ability to send commands to themedical device, (2) receive information from the medical device, and (3)be able to present to the patient at least a portion of the informationit receives from the medical device. In preferred embodiments, thepatient interacts with the medical device via the communication deviceat least once per week, on average, more preferably at least once everyother day, on average, and most preferably at least once per day, onaverage.

The implantable medical device (MD) includes a biocompatible housing; areservoir within the housing for holding a quantity of insulin; a sideport that attaches to the side of the housing, a catheter, that connectsto the side port; a pumping mechanism, within the housing for moving theinsulin from the reservoir through the sideport and through the catheterto the body of the patient; and control, monitoring, and communicationelectronics located within the housing. In alternative embodimentsvarious portions of implantable medical device hardware may be locatedoutside the housing. For example, the pumping mechanism or a telemetryantenna may be located within the sideport or other side mountedhousing; or a telemetry antenna may mounted on the outside surface ofthe housing, or extend along the catheter

The external communication device (CD) communicates commands to themedical device, receives information from the medical device, andcommunicates system status and system history to the patient. Theexternal communication device includes a housing; a keypad mounted onthe housing; a display forming part of the housing; and control,monitoring, and communication electronics located within the housing. Inalternative embodiments, the keypad may be replaced in whole or in partby a touch sensitive display or a voice recognition system. In addition,or alternatively, the display may be replaced in whole or in part by aspeech generation system or other audio communication system.

The outer appearance of the implantable device 2 is depicted in twopieces in FIGS. 1 a and 1 b and includes housing 6 having a drug outletport 8, and a refill port 12, a removable sideport 14 that mountsagainst the side of the housing 6 over outlet port 8, and a catheter 16having a distal end 18 and a proximal end that attaches to sideport 14.In alternative embodiments, the implantable device may take on adifferent shape and/or the sideport may be removed in favor of apermanently mounted catheter assembly.

The outer appearance of the external communication device 32 is depictedin FIG. 2. The various components of the external communication deviceare fitted in or on housing 34. Housing 34 is divided into a frontportion 34 a and a back portion 34 b. The front portion 34 a is providedwith an opening in which an LCD panel 36 is positioned. The panel 36 hasa lower portion that is a bit map display and an upper portion thatprovides icons and fixed element displays. The front portion 34 a of theexternal communication device is also provided with a five-elementkeypad 38. A first key 38 a is not located under a raised pad and doesnot provide tactile feedback when it is touched and may be used forspecial functions. The remaining four keys 38 b, 38 c, 38 d, and 38 ehave raised pads that provide tactile feedback when they are depressed.These remaining keys may be used in normal device operation and areknown as the select key, the up arrow key, down arrow key, and theactivate key, respectively. The back portion 34 b of the housing isfitted with a door under which a compartment is located for holding areplaceable battery.

The implantable device includes a memory for storing program code anddata. A portion of the memory in the implantable device is preferablyused to store configuration information for the external communicationdevice and for the implantable device itself. This allows theconfiguration data to be reloaded into a replacement externalcommunication device if the original should be lost or damaged. Thismemory is also used to store system operation information in the form ofactivity logs and counters, such an insulin delivery log. Variousportions of the contents of implantable device memory are downloaded tothe external communication device periodically. The downloads to theexternal communication device may occur manually, automatically, orsemi-automatically.

The implantable device control electronics include various self-checkingmechanisms to ensure that reliable operation of the system occurs. Forexample, as the pumping mechanism in this first embodiment requires afiring voltage that is significantly greater than the supply voltage, apre-fire voltage on the pump firing circuit is checked to ensure it islarge enough to cause the pump to execute a full stroke. After firing,the voltage is checked again, to ensure that discharging of the circuitoccurred. Each processor is monitored by a watchdog circuit that must beserviced, periodically. As implemented in the software, servicing mustoccur at both the interrupt level and at the mainline code level toensure that the processor has not malfunctioned at either level. Insulindelivery calculations are performed by both processors in such a mannerthat both processors must agree on the quantity and timing of insulindelivery. If an error of a significant nature is found in the system,the implantable device may be placed in a protective mode (i.e. suspendmode or stop mode) where insulin delivery is cut back to a medicallyinsignificant rate (e.g. about 1 pump stroke per hour) or stoppedcompletely. It is preferred to have a small amount of insulin bedelivered periodically to help prevent the occurrence of catheterblockage. In any event, if system failure does occur the systemeffectively stops delivery and attempts to warn the patient.

As the implantable device is controlled by messages that it receivesfrom the external communication device, messages sent to the implantabledevice have their accuracy and appropriateness checked with varyingdegrees of scrutiny depending on the critically of the message.

First, for example, all most all messages are sent from a particularexternal communication device to a particular implantable device usingexplicit identification information of the receiver to identify itselfas the intended recipient. It is considered desirable to useidentification information with messages that relate to medicaltreatment (e.g. the changing of insulin infusion rates). Moreparticularly it is desirable to use identification information withmessages that relate to changing medical treatment in a way that couldhave acute ramifications (e.g. to over supplying a drug such as insulinas opposed to under supplying the drug).

Second, the identity of the sender is preferably embedded implicitly inthe message. This implicit embedding occurs by using the identificationinformation of the sender in calculating a cyclical redunancy code (CRC)that is sent with the message. As such, the implantable device must knowthe identity of the sender in order to successfully check the content ofthe message against the transmitted CRC.

Third, the values of the data in the message are compared to anoperation code (Op Code) sent with the message to ensure that the codeand data are compatible. This Op Code is also used to set the size ofthe most messages, thereby providing a mechanism to increase electricalefficiency of the system by providing a way to limit reception time toonly that amount necessary to receive a particular message.

Fourth, if the message pertains to drug delivery, the message is sentwith redundant data that must match for the message to be interpreted asvalid. If for any reason the message is interpreted as invalid, themessage is ignored.

To avoid problems associated with long transmissions that may otherwisecontain long strings of non-transitioning data (i.e. long strings of 1sor 0s), the data portion of most messages are randomized prior totransmission and de-randomized upon receipt. For energy savings and timesavings, randomization and de-randomization preferably occur in a singlepass through the data and preferably utilize the semi-random attributesof the CRC tables from which CRC codes are built.

In the event that an error or other significant event occurs in theimplantable device, the device may attempt to inform the patient of theevent by sending a telemetry message to the external communicationdevice or alternatively by activating an audio alarm mechanism withinthe implantable device itself.

The implantable device is preferably configured so that the softwarerunning in it can be replaced or upgraded if the need should arise. Thesoftware may be downloaded into the implantable device throughtelemetry. The implantable device may be operated under two types ofsoftware: (1) bootloader code, or (2) application code. The bootloadercode may be broken down into first stage boot loader code which isstored in the ROM that is internal to the ASIC and second stagebootloader code that is stored in a SEEPROM or other non-volatile memoryassociated with each ASIC. The bootloader code and application code aredifferent for each ASIC.

The bootloader code does not care about the application in which theimplantable device may be used. The bootloader code is not concernedwith whether, the implantable device is an infusion device, a sensor, astimulator, or the like, or a combination thereof. On the other hand,the application code is concerned with the medical functionality of thedevice and thus is designed specifically for a given type ofapplication. As such, if an implantable device includes a pump and wasinitially configured (i.e. loaded with specific application software) towork with one drug (e.g. insulin) in one manner (e.g. allowing differentpreprogrammed basal rate changes to occur at the beginning of each halfhour of the day and allowing simultaneous use of an immediate bolus andan extended bolus), it could be reconfigured to operate in a completelydifferent manner while using the same drug or a different drug by simplychanging its application code. The replacement of application code inthis context is different from a mere change in program variables thatmay allow various control limits to be changed or even to allow the codeto execute different algorithms that are preexistant within the code.The replacement of application code in this context involves thereplacement of at least portions of the code that set forth programalgorithms.

When operating under control of the bootloader code, the implantabledevice allows certain telemetry operations to occur and also allowsdownloading of new application code, but does not allow any drugdelivery. The application code when controlling the system, on the otherhand, knows how to handle drug delivery but is not capable ofdownloading new code, or otherwise modifying itself (other than toaccept changes in parameter values). The bootloader code is alsodesigned and operated in such a way that new bootloader code can bedownloaded to the SEEPROM if an upgrade is felt to be appropriate.

In alternative embodiments, it is possible to merge the functionality ofthe second stage bootloader code and the application code into a singlepiece of code that can be upgraded as desired. In still furtherembodiments, it may be possible only to upgrade the application code andnot the second stage bootloader code.

As noted above, the implantable device assembly includes a detachablecatheter and sideport that provides a pathway for the insulin to adesired infusion location in the patient's body (e.g. into the patient'speritoneal cavity). The sideport allows for non-surgical diagnosis of acatheter blockage by using pressure. The sideport allows introduction ofa refill needle and small syringe to clear an obstructed catheter (e.g.using up to 110 psi of pressure). The sideport also allows theintroduction of a refill needle and a pipet to verify pump stroking. Thecatheter includes a check valve that seals (e.g. at between 0.5 to 3psid) and provides a redundant valve outside the pump to preventmedication or body fluids from back flowing into the implantable devicereservoir. The sideport in conjunction with the check valve facilitatesrinsing the fluid path within the implanted device with sodiumhydroxide, or other functionally similar material, by allowing effluentto be drawn out the sideport rather than pumped out the catheter tip. Inalternative embodiments, a sideport may not be used.

As noted above, the external communication device has both an audioalarm and a vibrator for alerting the patient or user of warnings andalarm conditions. The user has some control over the selection of audioalarm or vibration while the system can automatically switch fromvibration to audio if the vibrational alarm is not responded to in atimely manner. The audio alarm is programmable to emit at differentfrequencies, at different volume levels, for different durations, andwith different repetition patterns. These various alternatives are usedto signal different conditions. The vibratory alarm is also programmableto go off for different durations and with differing repetitionpatterns. In alternative embodiments, only one type of alarm may be usedand it may be used with or without different frequencies, volumes,durations, or loudnesses.

The software controlling the external communication device ispermanently stored within the external communication device using anon-volatile memory such as a serial electrically erasable programmableread only memory (SEEPROM) and is transferred to random access memroy(RAM) for execution. The code being executed in RAM can be reloaded fromthat SEEPROM as needed. Software located within the SEEPROM can bereplaced with new software under controlled conditions. The externalcommunication device is provided with sufficient memory capability tostore a duplicate, or upgrade, version of application software for theimplantable device as well as to store about 120 days of operationaldata. Under controlled conditions the external communication device maybe reset to its default configuration automatically (i.e. upon commandwithout the user having to specifically identify specific parametervalues). In alternative embodiments the software may be stored in adifferent device (e.g. a physical ROM, volatile RAM, non-volatile RAM,or in a replaceable plug in module). The software may be divided intobootloader and application code portions.

As noted above, the implantable device and external communication devicecommunicate with each other through radio frequency telemetry wherereception and transmission within the implantable device uses an antennathat is located within the metalic device housing based on a carrierfrequency that allows an acceptable amount of signal to penetratethrough the housing and through the human body. In alternativeembodiments, an antenna for the implantable device may be placed on thehousing or be otherwise located external to the housing so that outgoingand/or incoming signals need not penetrate the housing material. For thepresent embodiment the preferred frequency is either about 131 kHz orabout 262 kHz. The preferred data transfer rate is at about 8200bits/second. In alternative embodiments, different carrier frequenciesmay be used, e.g. from tens of kilohertz to thousands of megahertz. Alsoin alternative embodiments other data transfer rates may be used. Theexternal communication device and implantable device are configured andoperate together to provide rapid feedback to the operator. For example,a response to a basal rate or bolus programming telemetry interaction ispreferably provided to the patient within no more than 20 seconds andmore preferably within less than about 10 seconds, and most preferablywithin less than about 5 seconds.

Each implantable device and external communication device are preferablyassigned unique telemetry identifiers and a particular implantabledevice and particular external communication device are made to undergoa linking process (alternatively known as a marrying process) sosubstantive communication (e.g. communications that allow the externalcommunication device to control the medical operation of the implantabledevice) is limited to a joined pair. The communication link between theexternal communication device and implantable device provides variouslevels of checking and confirmation to minimize the possibility of theimplantable device receiving and then acting on an erroneous deliverycommand message. In alternative embodiments unique identifiers may besupplied to only one of the implantable or external communicationdevices, or even non-unique identifiers may be utilized.

The linking or marrying process is completed prior to a externalcommunication device being allowed to send drug delivery commands orupdated software to a particular implantable device. In this embodiment,each time an external communication device is replaced or reset, themarrying process must be repeated. The marrying feature provides themechanism to configure an implantable device to communicate with aparticular external communication device. This is carried out when theimplantable device and the external communication device are initiallyconfigured. The linking process requires positive assertion from theuser indicating that external communication device is linking to thecorrect implantable device. The linking process starts with the externalcommunication device sending an interrogate message to all implantabledevices within range by using a universal identifier. Each implantabledevice that is within range responds to the external communicationdevice's interrogate message by sending a response that includes patientidentity information as stored in that particular implantable device. Ifthe desired implantable device is the first to respond to theinterrogate signal, the user can acknowledge his/her desire to link theexternal communication device and the implantable device. Otherwise, ifthe first responding implantable device is not the one to be linked to,the patient may indicate so and that particular implantable deviceidentifier is added to a temporary exclusion list and the interrogatemessage is resent (including the exclusion list). When the interrogatemessage is received by each implantable device, only those whoseidentifiers are not in the exclusion list will attempt a response,thereby allowing other implantable devices within range to respond andbe heard. Once the correct implantable device is the one that has itsresponse displayed by the external communication device, the user canelect to start the linking process. Once the link is established, theimplantable device is made to enter suspend mode and then the user mustreprogram all basal rates including temporary basal rates that were inprogress, profile basal rates, and delivery patterns. In alternativeembodiments, all or a portion of this information may be retrieved fromthe implantable device, assuming it was programmed previously, but inthis particular embodiment as an added measure of safety, it waspreferred that these parameters should be reprogrammed so that the useris made to provide a positive assertion that he/she knows the deliveryparameters that the implantable device is using. During the linkingprocess the external communication device obtains other data from theimplantable device that it requires in performing its operations, e.g.the external communication device obtains stroke volume information forthe pulsatile pump and obtains insulin concentration data that is storedin the implantable device.

The sending and receiving of IR signals by the external communicationdevice is based on basic IrDA standards. In the present embodiment, thetransfer rate for the IR link is about 115 kbits/second. Of course inother embodiments other baud rates may be used or even automaticallyselected between. The IR link may be used to (1) upload new software tothe external communication device from a second external device, (2)download system operation information to the second external device forfurther analysis as desired, and/or (3) pass commands/responses to orfrom a second external device from or to the implantable device. Thesecond external device may be personal computer running appropriatesoftware or a more specialized system. The communications sent over theIR link are based on protocol details that ensure that only intendedmessages, and correctly received messages, are received and acted upon.

In an alternative embodiment a second or third external communicationdevice may be used in conjunction with the first external communicationdevice or as a temporary or partial replacement therefor. For example,at night, a chest strap, wrist watch, mattress pad, or the likecontaining appropriate telecommunication capabilities might be used as arelay device to pick up warning signals or other communication signalscoming from the implantable device and then to transmit them to thefirst external communication device or a third external communicationdevice so that a warning may be sounded to wake up the patient, todirectly notify emergency personnel of a problem, or to notify othermonitoring personnel in a timely manner of medical device operation orpatient condition. Such notification may occur using any appropriatetelecommunication systems, such as telephonic or internet connections.In the case of directly warning the patient, if the second communicationdevice has sufficient power and functionality it may implement thewarning signal directly. The second or third external communicationdevices may communicate with the first external communication device viaRF telemetry, IR communication link, optical link, galvanic connection,inductive communication, or the like.

The implantable device of the present embodiment has various deliverymodes. One of these modes is the suspend mode wherein the system iscaused to reduce insulin delivery to a clinically insignificant amount(e.g. 1 pump stroke (approximately 0.2 units of insulin assuming astroke volume of 0.5 microliters and a U-400 insulin concentration) perhour. It is intended that this minimal rate of delivery keep thecatheter open. The “suspend mode” mode may be used to interrupt deliveryof a bolus, priming bolus, profile basal rate, diagnostic rate, and/ortemporary basal rate. The system is programmed to alarm periodically toindicate to the user that the system is delivering insulin at aclinically insignificant rate. The user may exit suspend mode and resumebasal delivery. In this embodiment, any bolus that is in progress whensuspend mode is asserted is canceled such that any undelivered portionwill not be delivered even when suspend mode is cleared. Other than whenentering suspend mode through the linking process, if the implantabledevice is delivering a temporary basal rate when suspend mode isentered, the temporary basal rate duration continues while the pump isin suspend mode, and the temporary basal rate is reasserted when suspendmode is cleared for any portion of the duration that has not alreadylapsed. Of course in other embodiments other control options may beimplemented with regard to going into or coming out of a mode analogousto suspend mode.

The external communication device is programmable using an audio bolusmode. This mode allows a user to program the delivery of a bolus withoutlooking at the external communication device display. This mode providesan audio feedback to the user to indicate the amount of the bolus thatis being programmed. The audio bolus feature allows programming ofimmediate boluses. Immediate boluses are those that specify a quantityof insulin to be delivered in as short a time as possible, e.g. a shortas time as necessitated and allowed by any required repeated operationof the pumping mechanism. Under selected conditions a parameterselection may be made that dictates the incremental increase in bolusamount with each successive key entry (e.g. press of the Up-Arrow Key)when in audio bolus mode. Under selected conditions, the externalcommunication device provides another parameter that enables or disablesthe audio bolus feature. In the present embodiment, once the desiredbolus amount has been achieved by the repeated pressing of the selectkey, the user may confirm the accuracy of the selected amount bypressing a different key (e.g. the ACT key). When this confirmation keyis pressed for the first time the external communication device plays asequence of audio tones so as to indicate the amount programmed. If theamount is correct the user may press the ACT key again to initiatedelivery. If the amount is incorrect the user may simply wait apredetermined, but short, period of time for the external communicationdevice to time out or alternatively, the user may press any key otherthan the confirmation key. A distinct sound is emitted to indicate thatdelivery was not initiated, at which point the user may simply startover with the audio or visual programming.

Of course in other embodiments, other key press sequences may be used inthe performance of programming an audio bolus. Alternatively, if thesystem were configured with a microphone or other sound transducer andappropriate audio command recognition software or hardware, audioprogramming could be performed without any keystrokes or with a singlekeystroke to activate the external communication device's listeningmode. In a similar vane, if the external communication device wereconfigured with a sound transducer and appropriate speech enablinghardware and/or software, then instead of sounding a series of beeps toindicate program status, it could communicate to the user, in apredefined language, to indicate the status. In still furtheralternatives, speech recognition and/or speech generation hardware couldbe used to replace or supplement keypad or touch screen inputcapabilities.

In the present embodiment, basal rate delivery and bolus delivery may beprogrammed to occur in conjunction with each other as opposed to onereplacing the other. The system does not replace basal rate deliverywith bolus deliver but instead combines the amount to be delivered underbasal programming with the amount to be delivered under bolusprogramming to cause a net amount to be delivered that is equal to thesum of both amounts. The user may program a bolus amount on the externalcommunication device and the implantable device will respond bydelivering that amount. The amount of the bolus is subjected to a bolusmaximum as described below.

The system allows the user to program an amount to deliver that theimplantable device will deliver as quickly as possible using a requirednumber of pump strokes with typically no more than 6 seconds betweensuccessive pump strokes (e.g. 1-3 seconds per stroke). This type ofbolus is sometimes referred to as an immediate bolus or phase I bolus.

The system allows a bolus to be delivered where the user programs anamount and a duration. The implantable device delivers the amount as arate (i.e. number of pump strokes per unit time) for the durationspecified such that the amount programmed by the user is deliveredwithin the duration. This is analogous to a basal rate or temporarybasal rate delivery in some manner but is not identical as the totalamount to be delivered is the sum of this amount and any basal rate thatis currently in effect. Furthermore, in this delivery mode the user doesnot program the delivery amount as a rate. This type of bolus issometimes referred to a square wave or phase II bolus.

The system supports a “dual wave bolus” where the user programs anamount for immediate delivery (immediate bolus) and a second amount fordelivery during a specified duration (square wave bolus). Whenprogrammed in this manner the implantable device delivers the immediateamount as described above, followed by delivery of the second amountover the duration as a square wave amount also as described above.

The system also supports delivery of an immediate bolus while deliveryof a square wave bolus is in progress or while delivery of the squarewave portion of the dual wave bolus is in progress so long as theimmediate portion of the dual wave bolus has been completed.

The programming of boluses in the external communication device isfurther controlled by a variable bolus option. If the variable bolusoption is set to “no”, only immediate bolus programming is allowed andthe square wave and dual bolus options are removed from the menu choicesavailable on the external communication device. If the variable bolusoption is set to “yes”, immediate, square wave, and dual wave bolusprogramming are allowed and all menu options are presented to the user.

The implantable device holds a number of logs. One of these logs is abolus history log. In this log the implantable device maintains the timeand amount of boluses that have been delivered. This log contains themost recent boluses that were delivered. This log is set to contain upto a predefined number of boluses after which the log wraps around anddeletes older entries in favor of recording new entries. The externalcommunication device receives these records from the implantable device.These records may be viewed on the external communication device oralternatively they may be downloaded to a second external device wherethey can be viewed in numerical form or be plotted for viewing ingraphical form. The storage of this log information in the implantabledevice ensures that historical information remains available even in theevent that the external communication device is lost, damaged, orotherwise fails. Each time a new bolus is programmed from the externalcommunication device and confirmed by the implantable device, thedetails of the previously delivered bolus are provided back to theexternal communication device so a log maintained in the externalcommunication device is almost as up to date as the log maintained bythe implantable device. The log maintained in the external communicationdevice can be scrolled through for review by the patient or healthcareprovider. Each bolus history record includes the amount, time, and dateof the bolus delivery.

The implantable device maintains another log that provides the totalamount of insulin delivered by date. The implantable device maintains ahistory of the most recent 120 days of insulin delivery totals with thedaily total separated by basal delivery and bolus delivery. The dailytotals are downloaded automatically or semi-automatically from theimplantable device to the external communication device each day. Aswith the bolus log, this information is protected from loss or failureof the external communication device by its retention in the implantabledevice.

The system maintains multiple sets of basal rates where each setdictates basal rate delivery for a selected interval of time and eachelement in each set dictates the basal rate delivery for a subset ofthat selected interval of time. In the present embodiment the number ofsets is three, the selected interval of time is 24 hours beginning atmidnight, and the subset of the selected interval of time is 30 minuteswhich starts at the beginning of each half hour mark during the day. Assuch, each set consists of up to 48 rates that can start on anyhalf-hour of the day.

For programming convenience, the delivery rates need not be entered foreach subset but instead only for those subsets that represent a changein delivery rate compared to the previous subset. As such, in thisembodiment, basal rate values are only entered for the subset half hoursin which transitions occur and are entered by specifying the start timesand rates. Up to three 24-hour profiles may be entered with only one ofthe profiles selected as active at any given time. When a profile ismade active, information about that profile is communicated to theimplantable device to replace any other basal rate information retainedthere. As an added safety feature, only one profile set is stored in theimplantable device at any given time. The active profile is repeatedlyused day after day to control basal rate delivery in the implantabledevice until it is replaced by a different or revised profile. Suchbasal profile sets may be used for different types of days, e.g. workdays, non-work days, exercise days, non-exercise days, sick days, highstress days, and the like.

The system allows a temporary basal rate to replace any profile basedbasal rates during a specified period. This feature allows the user toprogram a basal rate without changing the basal profile. When thetemporary basal rate duration lapses, the implantable device resumesdelivery of the basal profile rate that is then in effect based on theselected profile and the then current time of day. The temporary basalrate, for example, may be utilized to program lower basal rates duringperiods of exercise, or used to program higher rates during periods ofhigh stress.

Selected “personal events” are recordable by the user in a personalevent log. The personal event log is accessed through the externalcommunication device and stored in the external communication device. Inalternative embodiments these events may be communicated to theimplantable device for safekeeping. The user may record the time thatcertain events occurred, such as exercising, meals, or illness. Aparameter may be set so as to disable personal event logging. Whendisabled, the option does not present itself on the user menu in theexternal communication device. In the present embodiment, the systemprovides sufficient memory and control for retention and review of up to100 such events.

“Automatic Off” is another feature of this embodiment. When this featureis enabled the insulin delivery system turns itself off if the user doesnot interact with the implantable device through telemetry for aprogrammed amount of time. This feature may be enabled or disabled. Inthis context, the turning off of the implantable device refers to theimplantable device going into suspend mode. The implantable devicealarms if it goes into minimum delivery mode as a result of theautomatic off interval lapsing. The automatic off interval is reset eachtime the implantable device receives a valid telemetry message from theexternal communication device intended specifically for it. In order tosave battery power in the implantable device, the external communicationdevice is programmed to track the time that elapses betweencommunications and to alarm 5 minutes before the automatic off intervallapses. This enables the user to clear the alarm and interact with theimplantable device before the implantable device itself alarms and thusresults in reduced power consumption by the implantable device.

An additional parameter of the present embodiment is bolus maximum whichspecifies the size of the largest single bolus that can be delivered. Apumping operation used in setting up the implantable device, calledpriming bolus is not subject to this maximum. The external communicationdevice is programmed so that a user can not program an immediate bolusamount greater than the bolus maximum. The external communication deviceis also programmed so that the sum of the immediate amount and theextended amount of a bolus (regardless of the duration) may not exceedthe Bolus Maximum. The implantable device uses the bolus maximum as asafety check of each bolus request that is received from the externalcommunication device.

The external communication device is programmed to sound a maximum alarmif the user attempts to deliver an amount of insulin during a predefinedperiod that exceeds a predefined limit. In this embodiment thepredefined period of time is one hour and the maximum alarm is termedthe hourly maximum alarm and the predefined limit is 2.5 times the BolusMaximum. This alarm is intended as a safety alert to the user and not asan absolute limit on the amount that can be dispensed in any one hourperiod. The external communication device is programmed to compute thetotal amount of bolus delivery during the previous one hour period eachtime a bolus is programmed. If the amount already delivered summed withthe programmed amount exceeds 2.5 times the programmed bolus maximum,the external communication device alarms and the bolus is not allowed.When an hourly maximum alarm is cleared, there is a short window wherethe user may program a bolus that normally would trigger an hourlymaximum exceeded alarm. Following the short window, bolus programming issubject to the hourly maximum limitation and warning again. In thepresent embodiment the short window is set at ten minutes. In thepresent embodiment both amounts programmed for an immediate and squarewave boluses are considered in triggering the hourly maximum exceededalarm regardless of when the extended bolus amount was or is to bedelivered. In alternative embodiments, the external communication devicemay be programmed to take into account quantities that have or will bedelivered within a one hour period based on the programmed amounts andtime intervals. In other embodiments the maximum amount in thepredefined period may be determined based on something other than themaximum bolus amount. In still further embodiments the maximum bolusamount may be implemented as a hard limit. In still further embodiments,a second or subsequent bolus programmed in the same short window wouldnot be subject to the warning. In other embodiments, the externalcommunication device could not only warn the patient that the maximumamount has been exceeded but would also indicate the amount that wasdelivered in the period being considered.

External communication device programming and implantable devicedelivery are also limited by a basal rate maximum which is the highestrate that may be delivered using a profile basal rate or a temporarybasal rate. A delivery rate used for diagnostic purposes known as thediagnostic rate is not subject to this maximum. The externalcommunication device is programmed to inhibit the user from entering abasal rate greater than the basal rate maximum. The implantable deviceuses the basal rate maximum as a safety check of each basal rate that isprogrammed. The implantable device ignores delivery requests thatinclude basal rate amounts greater than the basal rate maximum. Theexternal communication device is configured to inhibit the user andphysician from setting a maximum basal rate that is less than any of thebasal rates already programmed including those in the profiles that arenot currently active.

The external communication device is capable of displaying an estimateof the amount of medication remaining in the insulin reservoir. Theexternal communication device is programmed to alarm when the medicationremaining becomes less than a predefined low-reservoir threshold. Aswith other alarm conditions in the system, low-reservoir thresholdalarms are reasserted after clearing if appropriate actions have notbeen taken to resolve the condition that gave rise to the error or event(e.g. refilling of the reservoir has not been completed). Once thelow-reservoir alarm is cleared, and a predetermined period of time haslapsed and the system determines that the reservoir has not yet beenrefilled, the alarm will be reasserted so as to provide the user with areminder to have the reservoir refilled.

The implantable device and external communication device retain clinicalhistory information as records of various events that the system tracks.For example, events that stop the delivery of insulin such as alarms arerecorded in the clinical history. User-initiated events such as suspendmode that stop the delivery of insulin are also recorded. Refills arealso recorded. The system also contains logs for system diagnostics suchas implantable device battery levels. Through menu options the user mayview these various history logs.

In this embodiment, the system is programmed to allow a user to initiatea self test in both the external communication device and theimplantable device. If there are any error conditions detected, they arereported to the user. The system self test includes a number ofdifferent checks: (1) implantable device memory, (2) externalcommunication device memory, (3) implantable device piezo operation, (4)external communication device piezo operation, (5) externalcommunication device vibrator operation, and (6) external communicationdevice display. If an error is detected, the system reports the error tothe user using visual, vibrational or audio alarms.

The external communication device is configured to emit audio alarms, orto vibrate, in the event an alarm condition exists. The implantabledevice always emits an audio alarm if an error condition persists beyonda predefined amount of time based on the particular alarm condition thatexists. The external communication device is configured to allow theuser to selected audio or vibration notification when alarm conditionsexist. For many alarm conditions, the implantable device is programmedto contact the external communication device by telemetry prior tosounding an alarm on its own. In the event that the externalcommunication device receives the message and successfully notifies theuser of the condition and the user clears the alarm prior to apredefined time period passing, the implantable device does not soundthe alarm directly on its own. In the event that the alarm condition iscleared but not resolved, the implantable device may directly reassertand sound the alarm later or may reassert and recontact the externalcommunication device through telemetry.

The system supports an audio feedback mode where the implantable devicemay be programmed to beep on a first predefined number (e.g. 3-10 pumpstrokes after a rate change, and for a first predefined number (e.g.3-10) pump strokes of a bolus. In other alternative embodiments, otherfeedback techniques may be implemented.

The system supports a storage mode for the implantable device and forthe external communication device. Storage mode in the implantabledevice is a state where there is no drug delivery and no alarms and thefrequency of waking up to listen for incoming telemetry messages isreduced. Storage mode in the external communication device is a statewhere the screen is blank and no user functions are available. Theimplantable device is programmed to enter storage mode upon receipt of aparticular telemetry command. The implantable device is programmed toexit storage mode by receipt of a particular telemetry command. There isno implantable device alarm that indicates that the implantable deviceis entering storage mode.

The external communication device is programmed to enter storage mode ifthere is no user interaction with the external communication device foran extended period of time (e.g. 5-10 days). The external communicationdevice is programmed to exit storage mode in the event of userinteraction with external communication device such as button presses.When the external communication device is in storage mode the screen isblank and the external communication device hardware is put into alow-power state.

The system allows refilling of the pump and reporting on deliveryaccuracy. The system is programmed to allow entry of an extracted volumeand a fill volume during the refill process. The external communicationdevice may be made to display delivery accuracy based on a differencebetween the expected amount remaining in the insulin reservoir and theactual amount of insulin removed during the refill process.

In the present embodiment, the system is configured to support user andphysician programming of the delivery options using insulin units basedon a desired resolution value not based on a predetermined pump strokevolume. When the external communication device is programmed to delivera certain amount of insulin, the external communication devicecalculates the number of pump strokes necessary to deliver that quantityand passes the pump stroke information onto the implantable device. Thepump stroke information is passed in fixed point format including bothan integer portion and a fractional portion. The determination of pumpstrokes is based on the implantable device pump stroke volume and theinsulin concentration.

The system of this embodiment is configured to allow a programmingoption to be set that allows the physician to prime the catheterquickly. As will be discussed further hereafter, this option is onlyavailable as a supervisor function. The priming function/option triggersthe implantable device to deliver an amount of insulin large enough tofill the catheter. In this mode, pump strokes are delivered as fast aspossible. The physician is notified when the priming bolus is completed.

The system supports a special rate called diagnostic rate that is onlyprogrammable as a “supervisor only” function. This special rate is usedin determining delivery accuracy. The diagnostic rate function triggersthe implantable device to deliver at a programmed rate that is notsubject to the basal rate maximum.

In this embodiment, the setting of system maximum basal rate and maximumbolus amounts may be programmed to be inaccessible to the patient andonly accessible through a supervisor menu. The patient's ability toaccess these maximum values is controlled by a maximum lock parameterthat is a supervisor function. When the maximum lock feature is enabled,the user may view, but not change, the bolus maximum and the basal ratemaximum. When the maximum lock feature is disabled, the user may changethe bolus maximum and the basal rate maximum.

The system includes memory space and program capability to personalizethe external communication device and implantable device so thatinformation such as the patient name and physician name can be storedfor later retrieval and review. For example, the personal ID may be aslittle as 10 characters and as much as 200 characters or more. In thelinking process it is preferred that at least a portion of thisinformation be used in determining that the external communicationdevice has contacted the desired implantable device (assuming theimplantable device has already been previously programmed with identityinformation. When identification information is updated in the externalcommunication device it is passed on to and stored in the implantabledevice.

The system retains factory default information and may be reset to thosevalues when operating under supervisor control so that the system may beconfigured rapidly to a known state. The system may also be placed in astop mode or controlled to replace or reload implantable device softwarewhen operating under supervisor control.

As noted above certain system functions require special control andtheir access is restricted. These features are only accessible via asupervisor menu on the external communication device. The supervisormenu is password protected. The password may be set by the physicianwhile in supervisor mode. The supervisor menu system may also be enteredby using a factory password. The factory password may be derived fromthe system characteristics. For example, the factory password may be afixed number or character pattern. It may be based on a variableparameter, such as the date reflected by the external communicationdevice, and/or the time reflected by the external communication device,and/or the serial number of the external communication device.Supervisor options/functions include the following: (1) refill, (2)priming bolus, (3) diagnostic rate, (4) maximum lock, (5) personal IDsetting, (6) initialize to factory defaults, (7) download implantabledevice software, (8) stop pump, and (9) set supervisor password.

The user interface uses four keys, e.g. a SEL, ACT, UP and DOWN key, tonavigate through menus, display options and features, and to programvalues. The external communication device changes the display to theidle display which shuts off the bit map display if the externalcommunication device keypad is idle for a predefined period of time,preferably between 2 seconds and 30 seconds, more preferably between 4seconds and 15 seconds and more preferably between 5 seconds and 10seconds, e.g. 7 seconds, while the user is viewing options. The externalcommunication device may change the display to the idle display using adifferent predetermined time, e.g. a longer time such as 15 seconds, ifthe external communication device is idle while the user is in aprogramming or data entry screen.

As noted previously the system is programmed to display the current timeand date. The time may be displayed in either a 12-hour or 24-hourformat depending on user preference though in either event internalcalculations that require time are based on a 24 hour clock.

All time displays by the external communication device are shown in thesame format including time stamps on historical data and profile starttimes. This format in the present embodiment is based on a relative timemeasured in minutes since the factory initialization of the implantabledevice.

Acceptable parameter ranges for selected variables used in this firstembodiment are depicted in the following table. Of course, in otherembodiments other ranges are possible, other programming units may beused, some parameters may be converted to constants while otherparameters may be added as variables. Acceptable Parameter RangesParameter Name Values Automatic Off Duration Off, 1-16 hours Audio BolusIncrement 0.4 units or 0.8 units Bolus Amount 0.2 U to Bolus Maximum by0.2 U Bolus Duration 30 min to 4 hours Maximum Bolus 0.2 U to 35.0 U by0.2 U Hourly Maximum Bolus 2½ times the programmed Maximum Bolus BasalRate 0.2 U/hr to Basal Rate Maximum by 0.1 U/hr Temporary Basal Rate 0.2U/hr to Basal Rate Maximum by 0.1 U/hr Temporary Basal Rate 30 min to 24hrs by 30 min Duration Basal Rate Maximum 0.2 U/hr to 35 U/hr by 0.1U/hr Diagnostic Rate 10 to 150 u/hr by 10 u/hr in U-400 10 to 185 u/hrby 10 u/hr in U-500 Insulin Concentration U-400 or U-500

As noted above, both the implantable device and the externalcommunication device detect and report alarm conditions. The followingtable depicts examples of different types of alarms and examples ofassociated delivery states that are entered in response to the conditionthat gave rise to the alarm. Alarm Conditions ALARM Alarm ConditionAlarm State Action Low Battery Alarm when there is battery AlarmOnly/Icon energy remaining of about ON 8 weeks or less Depleted BatteryNone guaranteed No Delivery Low Reservoir Alarm when 2 mL of drug AlarmOnly/Icon remaining ON Empty Reservoir Alarm when 1 mL of drug AlarmOnly/Icon remaining ON Any implantable Alarm No Delivery device HardwareFailure Detect Over Delivery Alarm when disagreement from No Deliveryvarious delivery calculations produces a discrepancy of a first type.Under Delivery Alarm when disagreement from No Delivery various deliverycalculations produces a discrepancy of a second type. Self Test FailureAlarm when the periodic self No Delivery test including the memory testfails

As noted above, even when an alarm is initially cleared, it may bereasserted if the condition that gave rise to it continues to persist.When a condition persists, the reassertion of and sounding of the alarmmay occur for example as indicated in the following table. TABLE 1 AlarmReassertion Intervals Menu Persistent Internal Options Icon/MessageException Reassertion Beep Disabled Display Over Delivery  0  5 min YesYes Under Delivery  0  5 min Yes Yes Low Implantable  7 Days 24 Hrs N/AYes Device Battery Low Reservoir 24 Hrs 24 Hrs N/A Yes Empty 24 Hrs 24Hrs N/A Yes Reservoir Depleted N/A N/A N/A N/A Implantable DeviceBattery Automatic Off N/A  5 min N/A Yes

In this embodiment, physical and functional features have beenconsidered as well as implantable longevity. In addition to the variousfeatures noted above, the implantable device and external communicationdevice preferably meet certain physical targets: (1) The implantabledevice is preferably packaged in disk shaped housing that is thinnerthan about 1 inch, and preferably thinner than 0.9 inches, and morepreferably thinner than about 0.8 inches or less, with a diameter ofless than about 4 inches and more preferably about 3.2 inches or less,and having an empty weight of less than about 180 grams and morepreferably less than about 165 grams, and (2) The external communicationdevice has been packaged in a somewhat rounded but nominally rectangularshaped package having dimensions of less than about 1.0 inch by 3.5inches by 4.0 inches, but more preferably having dimensions about 0.8inch or less by about 2.8 inches or less by about 3.5 inches or less,and weighing less than about 6 oz. In other embodiments, various otherdevice shapes and sizes may be used.

The implantable device and external communication device are preferablyalso designed and are controlled to meet certain longevity requirementsin combination with the desired functional requirements. It is desiredthat the implantable device remain operational within the body of apatient for a period of about five years or longer, more preferably aperiod of about seven years or longer, and most preferably a period ofabout 9 years or longer. As the present embodiment uses anon-rechargeable battery, the longevity of the implantable device isprimarily dictated by the power consumption of the electronic modulesand the capacity of the battery. The determination of longevity iscomplicated by the fact that the power consumption of the electronicmodules is not constant over time but varies depending on the actionsthat are required by the user. Two elements of the preferred embodimentthat lead to an acceptable level of longevity are the use of low powerelectronic circuit elements and the controlled application of powerand/or clocking signals to various modules. The power and/or clockingsignals are supplied to the modules on an as needed basis andoperational protocols have been put into place to minimize the amount oftime that the various modules need to operate. As noted previously, anexample of such protocols include the implantable device's attempt tocommunicate with the external communication device by telemetry prior tousing a more power consumptive internal alarming process. Anotherexample involves the implantable device having a storage mode that usesless power than a normal operational mode. A further example includesthe implantable device's process of turning on its receive telemetry forshort periods of time (about four milliseconds) on a periodic basis(once every two seconds) to listen for incoming messages and thenshutting off the telemetry system if no messages are incoming. Anadditional example, includes the processor's ability to turn itself offwhen it is not needed and to be awakened by interrupt signals whenneeded. These and other examples of controlled power consumption arediscussed further hereafter.

FIG. 3 depicts a simplified block diagram of various functionalcomponents or modules (i.e. single components or groups of components)included in the implantable medical device 2 and external communicationdevice 32. The external communication device 32 includes (1) a housingor cover 34 preferably formed from a durable plastic material, (2)processing electronics 42 including a CPU and memory elements forstoring control programs and operation data, (3) an LCD display 36 forproviding operation for information to the user, (4) a keypad 38 fortaking input from the user, (5) an audio alarm 44 for providinginformation to the user, (6) a vibrator 46 for providing information tothe user, (7) a main battery 52 for supplying power to the device, (8) abackup battery 54 to provide memory maintenance for the device, (9) aradio frequency (RF) telemetry system 56 for sending signals to theimplantable medical device and for receiving signals from theimplantable medical device, and (10) an infrared (IR) input/outputsystem 58 for communicating with a second external device.

The second external device may include input, display and programmingcapabilities. The second device may include a personal computeroperating specialized software. The computer may be used to manipulatethe data retrieved from the communication device or the medical deviceor it may be used to program new parameters into the communicationdevice or directly into the medical device, or even used to download newsoftware to the communication device or to the medical device. Themanipulation of the data may be used in generating graphical displays ofthe data to help aid in the interpretation of the data. Such datainterpretation might be particularly useful if the medical deviceprovides data concerning a physiological parameter of the body of thepatient, such as a glucose level versus time. More particularly thecomputing power and display attributes of the second device might beeven more useful when the medical device includes both an implantedsensor (e.g. glucose sensor), or external sensor, and an implanted pump(e.g. insulin pump), or external pump, where the second external devicemay be used to enhance the ability to ascertain the effectiveness of thetwo devices working together. Successful control periods and problemcontrol periods could be more readily identified. In fact, if the twodevices work on a closed loop basis or semi-closed loop basis, theanalysis performable by the second external device may be useful inderiving new closed loop control parameters and/or in programming thoseparameters directly into the communication device or the medical deviceor devices.

The implantable device 2 includes (1) a housing or cover 6 preferablymade of titanium that may or may not be coated to enhancebiocompatibility, (2) processing electronics 72 including two CPUs andmemory elements for storing control programs and operation data, (3)battery 74 for providing power to the system, (4) RF telemetry system 76for sending communication signals (i.e. messages) to the external deviceand for receiving communication signals (i.e. messages) from theexternal device, (5) alarm or buzzer 82 for providing feedback to theuser, (6) refill port 12 for accepting a new supply of drug as needed,(7) reservoir 84 for storing a drug for future infusion, (8) pumpingmechanism 86 for forcing selected quantities of drug from the reservoirthrough the catheter to the body of the patient, (9) sideport 14 forproviding a replaceable connection between the (10) catheter and thepump housing and for allowing diagnostic testing of the fluid handlingsystem to occur, and catheter 16 for carrying medication from theimplant location to the desired infusion location.

In this embodiment, the pump mechanism is preferably a low power,electromagnetically driven piston pump. Such as for example Model Nos.P650005 or P650009 as sold by Wilson Greatbatch Ltd. of Clarence, N.Y.which have stroke volumes of 0.5 microliters and draw under 7 mJ (e.g.about 6 mJ) per pump stroke and under 4 mJ (e.g. about 3 mJ) per pumpstroke, respectively. The pump mechanism dispenses a sufficiently smallvolume of insulin per stroke so that a desired level of infusionresolution is achieved. For example if an infusion resolution of 0.2units of insulin were desired when using U400 insulin, then a strokevolume of about 0.5 microliters would be appropriate. In otherembodiments other types of infusion pumps may be used, e.g. peristalticpumps, screw driven pumps, and the like.

As depicted in FIG. 3, the implantable device includes a reservoir 84for holding a desired quantity of insulin. In this embodiment, the drugheld in the reservoir is preferably maintained at a slight negativedifferential pressure (with respect to the pressure on the outside ofthe housing) so that in the event of a leakage in the reservoir 84 orhousing 6, the drug will not be forced from the housing into the body ofthe patient. The drug is added to the reservoir 84 by means of atranscutaneous needle that is passed from a position exterior to thebody into self sealing refill port 12. Due to the slight negativepressure that the reservoir experiences, insulin in a syringe connectedto the needled is drawn into the reservoir without need of externalforce. The drug is extracted from the reservoir 84 and forced throughcatheter 16 by an electronically controlled pump mechanism 86. Inalternative embodiment positive pressure reservoirs may be used incombination with pumping mechanisms that force the medication or drugfrom the implantable device and/or used with flow restrictors thatdispensed the drug at a fixed rate or at a variable rate with the aid ofvalves or flow diverters.

The size of the reservoir is preferably large enough to hold sufficientinsulin so that refilling does not have to occur too often. For example,it is preferred that time between refills be within the range of 1.5-4months or longer, more preferably at least 2 months, and most preferablyat least 3 months. Opposing the containment of a large volume ofinsulin, is the desire to keep the implantable device as small aspossible. In the present embodiment the implantable device and reservoirhas been designed to hold about 13 ml of insulin. A preferred insulinhas a concentration of 400 units per milliliter and is available fromAventis HOE 21Ph U-400 from Aventis Pharma (formerly Hoechst MarionRoussel AG, of Frankfurt am Main, Germany). This insulin is a highlypurified, semi-synthetic human insulin with 0.2% phenol as a preservingagent, glycerol as an isotonic component, TRIS as a buffer, plus zincand Genopal® as stabilizing agents. This quantity and insulinconcentration allows about 2-4 months between refills. In otherembodiments higher insulin concentrations may be used (e.g. U-500 orU-1000) to increase time between refills or to allow reduction inreservoir size. In some embodiments, when higher concentrations areused, any quantized minimum delivery amounts may be reduced by modifyingthe pumping mechanism, control circuitry, or software control algorithmso that infusion resolution is not adversely impacted.

The external communication device contains appropriate software toprovide proper control of the device including appropriate functionalityto allow communication with the medical device, to allow adequatecontrol of the operation of the medical device, and to give appropriatefeedback to the user regarding overall system operation. The medicaldevice is provided with appropriate software to allow communication withthe external communication device, to allow safe and appropriateoperation of the medical functionality of the device, and to allowdirect feedback to the user concerning device status via the internalalarm.

The control electronics of both the implantable device and externalcommunication device are centered around microprocessor based integratedcircuits, i.e. processor ICs, that are implemented in the presentembodiment in the form of application specific integrated circuits(ASICs). Two such ASICs are used in the implantable device to increaseoperational safety of the device by configuring the device to requirethat the two ASICs act in conjunction with each other in order formedication infusion to occur.

In different embodiments, more or less of the control electronics may beimplemented within one or more processor ICs while any remainingportions may be implemented external to the processor IC(s). Theprocessor IC may be referred to as an MD processor if used in themedical device portion of the system or a CD processor if used in thecommunication device portion of the system. In other embodiments theprocess IC used in the communication device may be different, e.g. havea different CPU or different peripheral modules, from a processor ICused in the medical device. In embodiments where more than one processorIC is used in either the medical device or the communication device eachof the processors may be different. They may be specifically designedfor their intended roles when they perform at least partially differentfunctions. Depending on particular design constraints portions of theelectronics not embodied in the processor ICs may form part of one ormore hybrid circuit boards or be otherwise mounted within, on, or evenin some cases external to a device housing.

A functional block diagram of the Processor IC for the presentembodiment is depicted in FIG. 6. Each processor IC of the presentembodiment includes a CPU 912 and various peripheral modules that areused for system control, data acquisition, and interfacing withelectrical components external to the processor IC.

The peripheral modules of the processor IC of the present embodimentinclude (1) a non-volatile memory interface module, e.g. a SEEPROMinterface module 914, (2) a boot ROM module 916; (3) an SRAM module 918;(4) a memory decoder module 920; (5) a crystal oscillator module 922;(6) a timer module 924; (7) a pump interface module 926; (8) a watchdogmodule 928; (9) an RF telemetry module 930; (10) an interrupt handlermodule 932; (12) an analog-to-digital converter module 934; (13) an LCDclock driver module 936; (14) an alarm interface module 938; and (15)first and second synchronous serial interface modules 942 and 944. Thememory decoder module interfaces with the core processor, boot ROM, andinternal SRAM using a 16 bit address bus which also is available offchip for addressing external memory. With the exception of the crystaloscillator module all other internal module communicate over an 8-bitdata bus or 16-bit data bus. FIG. 6 further illustrates that the A/Dmodule may take input from sources internal to the processor IC andsimilarly the interrupt handler can take up to 9 interrupts from sourcesinternal to the processor IC. Additionally, most of the modulescommunicate with outside components or modules over one or moreinput/output lines.

In alternative embodiments fewer, additional, or different peripheralmodules may be incorporated into the processor ICs. In one extreme theprocessor IC may simply incorporate a CPU with all other modules beingexternal thereto. In the other extreme almost all, if not all,electronic components may be incorporated into a single processor IC.Intermediate alternatives might incorporate a single additional moduleinto the processor IC (in addition to the CPU), others might incorporatemore than one, e.g. 4 or more, 8 or more, or the like. In still otheralternatives, the number of peripheral modules or components in anentire device may be considered and more than a certain percentage ofthem incorporated into one or more processor ICs, e.g. more than 50%,more than 75%, or even more than 90%.

The processor ICs are responsible for basic system management andcommunication of information between the implantable device and theexternal communication device through the RF telemetry link. Thetelemetry systems of the present embodiment are implemented in partthrough electrical hardware and in part through software controlled by aprocessor IC.

In the present embodiment, most of the required electrical modules forthe implantable device are integrated within the processor ICs. However,several are not. These additional modules include two independentcrystal oscillators (one for each ASIC); two non-volatile memory modules(one for each ASIC), e.g. SEEPROM chips; a volatile memory module (usedonly by one of the ASICs), e.g. an SRAM chip; pump driver circuitry(partially controlled by the each ASIC); front end telemetry systemcircuitry; and voltage measurement circuitry associated with the pumpdriver circuit; a buzzer; and a battery.

Within the implantable device telemetry operations are controlled by asingle ASIC (sometimes known as the main processor). The other processor(sometimes known as the monitor processor) controls the buzzer and isthus responsible for audio communications coming from the implantabledevice. The medical functionality of the implantable device (i.e. theadministration of insulin in the present embodiment) is controlled byboth processors. To maintain the implantable device in a fail-safeoperational mode, these two processors must maintain an appropriatelevel of agreement concerning infusion instructions or a system reset isforced to occur. The main and monitor processors communicate with eachother through the use of hardwired serial input and output ports.

As with the implantable device, the control electronics of the externalcommunication device are centered around an ASIC that controls andinteracts with a number of peripheral modules. These peripheral modulesinclude an LCD display and driver, an IR port and driver, a crystaloscillator, a keypad and keypad interface, power management modules andreset circuitry, external volatile memory (e.g. SRAM) and non-volatilememory (e.g. SEEPROM), a buzzer, and front end telemetry hardware.

The external communication device (CD) is a hand-held device that allowsa user to program and communicate with the implantable device. Theexternal communication device of the present embodiment preferably has aweight of less than about ounces, a thickness of less than about 0.8inches, a width of less than about 2.8 inches, and a length of less thanabout 4.0 inches.

The external communication device is enclosed by housing 34 as depictedin FIG. 2 and includes within housing 34 a number of differentelectronic modules or components. These modules and a high level outlineof their interconnections are depicted in FIGS. 4 a and 4 b. FIGS. 4 aand 4 b, form the left and right halves of a single block diagram. Theelectronic configuration of the external communication device iscentered on an ASIC 502 which has been divided for presentation purposesinto left and right halves 502 a and 502 b.

The ASIC 502 includes a microprocessor, internal ROM, internal RAM and anumber of additional modules. A number of the ASIC modules used by theexternal communication device are depicted in FIGS. 4 a and 4 b. Thesemodules include (1) a watchdog 522, (2) an external reset 534, (3) anA/D converter 542, (4) a serial ROM port 572, (5) a first serialsynchronous interface port 592, (6) an RF module 612, (7) an oscillatormodule (650), (7) a tone alarm driver 682, and (8) LCD port 692, (9)three interrupt inputs, and (10) a number of I/O buses. According tothis first embodiment, the preferred ASIC for use in the externalcommunication device is identical to the ASICs used in the implantabledevice. Further details about the ASIC are provided hereafter.

The ASIC includes a first interrupt input 512 that receives interruptsignals 514 generated by a key interrupt generator circuit 516.

The ASIC includes a watchdog 522 and watchdog output 524 that is fedinto “OR” logic circuitry 526 that effectively performs an “OR”operation on three different signals. An output signal 528 of the ORlogic circuitry 526 is fed into an input 532 of the ASIC which in turnis connected to reset circuitry 534 that triggers the Processor IC to bereset. The Processor IC can be reset by making any of the three signalshigh which in turn will drive the output of the “OR” logic circuitryhigh and thus the input 532 high. The watchdog output signal 524 is madeto go high when the processor does not reset the watchdog in a timelymanner.

The ASIC includes analog-to-digital converter electronics 542 that usestwo external inputs 544 and 546 which are used, respectively, formeasuring a voltage (VAA) of a main battery and a voltage (VCOIN) of abackup battery.

The ASIC includes a second external interrupt input 552 that isconnected to battery failure detection circuitry 554 by line 556 thatcarries a high reset signal.

The ASIC includes an I/O bus 562 for carrying address, data and controlsignals to and from 1 megabyte of external SRAM 564 located on twoexternal chips. Each chip is a four megabit, low power SRAM, organizedas 256 k by 16 bits, operating between 2.7 and 3.6 volts, with a maximumstandby current of 15 μA. This memory may be accessed either byte-wideor word-wide, as controlled by two external ram signals from the ASIC.Furthermore, an additional two signals from the ASIC are used for chipselection and a third additional signal is sued for bank selection. Thethird additional signal uses the same output as did the pump fire signalon the monitor processor in the Implantable Device. I/O bus furtherprovides 17 address lines and 16 data lines.

A power management module 722, to be further discussed hereafter,produces a back up battery power signal 762 that goes high when the mainbattery 732 fails and power is being supplied by the back up battery752. When the signal 762 is high, access to the SRAM chips is disabledand thus memory access is denied. This is implemented to prevent memoryaccess during unstable periods and to tri-state the memory chip outputsso they are not driving low impedance inputs when boosted voltage 736(VCC), coming from up-converter 734 that is powered by the main battery732, fails.

The 762 signal and one of chip selection signals (depending on the SRAMchip being selected), are provided to the inputs of an OR gate and thesignal from the OR gate (not shown) is the control signal that is passedto the SRAM. As such, for the particular SRAM chip to be accessible boththese signals must be in their low states.

These memory chips are powered by power signal 756 (VPOS) that isderived from VCC when it is available and from the backup battery whenVCC is not available.

The ASIC includes a SEEPROM port 572 that is used to connect to twoexternal SEEPROMs 574 using a power output signal 576, a clock outputsignal 578, and a bi-directional data communication line 582. TheSEEPROMs may be identical chips, for example. They preferably have a twowire interface, are internally organized as 64 k by 8 bits, supportbi-directional data transfer, and use an operating voltage between 1.8and 3.6 volts. These chips are used to provide memory space for programcode and program data. The addresses of these two SEEPROM chips are setby hard wiring. Each chip has a capacity of 64 K bytes, organized as 512pages of 128-bytes each. Each SEEPROM is configured so that it can bewritten to as well as read from during run time by the system processor.

In the present embodiment one of the SEEPROMs is used for storingexternal communication device software which is loaded into internal RAMor external RAM during system boot up, while the other SEEPROM iscapable of holding software for download to the implantable device.

The ASIC includes a first synchronous serial interface port 592 that isfunctionally connected to an external UART 594 using several lines 596,including a single clock line for both incoming and outgoing data, adata-in line for data coming from the UART to the Processor, and adata-out line for data going to UART.

A third external interrupt input 602 for the ASIC is connected to UART594 by line 604. A high signal is generated on line 604 by the UART chipwhenever serial data is received through the IrDA port.

The ASIC also provides an RF telemetry module 612 which provides TXI andTXQ signals, on lines 614 and 616, to RF transmitter circuitry 618. TheRF telemetry module also provides a power signal 622 to RF receivercircuitry 624. The RF receiver circuitry provides a first and secondmixer input signals, 626 and 628, respectively, back to a mixer 632 inthe RF telemetry module 612. The RF module also provides a controlsignal 634 to switching circuitry 636 that effectively connects eitherthe RF transmitter circuitry to an antenna 638 or RF Receiver circuitryto the antenna 638. The control signal 634 is also provided to a NANDgate 642.

The RF telemetry system in the external communication device is similarto that of the implantable device in overall configuration and incontrol though some differences in circuit detail do exist. The RFsystem uses a carrier frequency of about 250 kHz (e.g. 262,144 Hz+/−125Hz). The RF telemetry subsystem is composed of analog and digitalmodules. The digital module includes a QFAST® modulator/demodulator, acontrol and timing logic circuit that are integrated in the ProcessorIC.

The analog module consists of an RF front-end circuit and a mixer. Themixer is also integrated in the processor IC. The RF front-end circuitconsists of RF transmitter circuitry and RF receiver circuitry, which isin-turn composed of a band-pass filter and a 3-stage amplifier.

The RF receive circuitry and transmit circuitry share the same antenna638. The antenna 638 is a faraday-shielded, air-coil, housed within thehousing of the external communication device. The antenna and thefaraday shield are connected to the printed circuit board.

The antenna is switched between transmit and receive functions in asimilar manner to that described above with regard to the implantabledevice. Switch 636 is similar to switch 234 of the implantable deviceand includes a tristate driver and an analog switch. The switch is alsocontrolled in an analogous manner. The transmitter 618 is substantiallythe same as that described above for the implantable device.

The RF Receiver 624 is similar to that used in the implantable device.As with the implantable device, the RF Receiver module 624 includesthree amplifier stages that are tuned to pass and amplify desiredsignals. In contradiction to the implementation in the implantabledevice, all three stages of in the external communication device aretuned. The first stage has its frequency response set by a tank circuitwith tuning adjustable by a variable capacitor. The signal from the tankcircuit is passed through a direct current voltage blocking capacitorand then on to a pair of transistors in a push-pull configuration. Thetransistors may be identical to those used in the implantable device.The second and third stages use tuned push-pull transistorconfigurations.

The signal resulting from these three stages has preferably beenamplified by 70 to 90 dB with an RF passband of about 16 kHz (e.g. about2¹⁴ Hz) centered around a 262,144 kHz carrier at the 2 dB ripplepeak-to-peak maximum. An RF stopband of about −65 dB is provided atbelow about 150 kHz and at above about 550 kHz.

The line carrying the output signal from these three stages is taken toground through a 100 kΩ resistor and then a 390 ρF capacitor. A firstsignal, RFI, is taken from the output signal prior to the output signalpassing through the resistor. A second signal, RFQ, is taken from theoutput signal from between the resistor and the capacitor. The RFI andRFQ signals are then passed onto the main processor IC. The RFI signalis the filtered and amplified RF signal that was received by thetelemetry system, while the RFQ signal is a direct current signal havinga voltage value equal to the average voltage value of the RFI signal.

The ASIC is also connected in parallel to a crystal oscillator 652 andassociated resistor 654 by lines 656 and 658.

The ASIC is additionally connected to a first output port 662 by an I/Obus 664 and a second output port 668 by an I/O bus 672. Each of thesetwo output ports may be formed from an octel tristate non-inverting Dflip-flop. These output ports are latching so that inputs from the CPUneed not be maintained constantly.

Address decoding and port enablement are provided by a single externalport and address decoder chip. This decoder is preferably a 1-of-8Decoder/Demultiplexer. This address decoder chip is used by both theoutput ports as well as the keyboard input port 702.

The output ports are enabled/disabled by the RESET signal 726. Such thatwhen RESET is asserted (low) due to the main battery voltage VAA fallingbelow a programmed threshold, the output ports are tri-stated. When thishappens, pull-up resistors set the outputs to appropriate states so thatall high current devices are shutdown. This is done to preserve theenergy stored in the VCC storage capacitors so it is only used forpowering the appropriate portions of the circuit for an orderlyshut-down.

The ASIC further provides tone driver circuitry 682 to an audio alarm 44(e.g. a piezo alarm) by lines 686 and 688 that carry first and secondbuzzer signals that are produced by the Processor IC.

The ASIC further includes a second synchronous serial interface port 692that functions as an LCD port for communicating with an LCD module 694that includes LCD driver and display 36 (FIGS. 2 and 3). Threecommunication lines 696 are used between the serial interface port andthe LCD module. One of the lines provides a selectable clock, fordriving the LCD, of either about 64 kHz or 32 kHz (i.e. about 2¹⁶ Hz or2¹⁵ Hz). An additional three control signals 782 are provided by outputport 662. These control signals include a chip select signal, a resetsignal, and a clock loop back signal.

The LCD of the present embodiment is powered by an LCD driver chip, suchas Part No. MC 141800A from Motorola. Communication to the LCD module isperformed using I²C serial communication protocol. The communicationlines are supplied directly from the second serial synchronous interfacecommunication port of the Processor IC.

The external communication device visually communicates to the patientusing an LCD display 36. This display includes a dot-matrix graphics LCDfor displaying a portion of the information to be conveyed and anicon/fixed segment display for displaying the remaining information tobe conveyed. The dot-matrix display allows various languages to bedisplayed with only a software change or change of a parameter(variable) within the software. In the present embodiment the dot-matrixportion has a display region of about 100×55 pixels.

FIG. 5 depicts the display 36 of external communication device 32including the icon/fixed display region 852 and the bitmap display area854. The icon/fixed element display bar includes a time-of-day indicator856 which is made up of 4 seven segment display elements, a “:” symbol,an “AM” symbol, and a “PM” symbol. The icon bar also includes a batterysymbol 858 that turns on when the main battery of External CommunicationDevice is getting low. The icon display also includes an alarm icon 860in the shape of a bell that is turned on when an alarm condition is ineffect. The icon display further includes a 4 segment reservoir levelindicator 862. When the reservoir is estimated to be full all foursegments are powered and as the estimated reservoir level dropsindividual segments are successively turned off. The icon displayfurther includes a circular display 864 comprised of 4 pie shaped wedgeelements. The number of pie-shaped wedges being displayed and theirmotion are indicative of the delivery condition that is currentlyactive. A month indicator 866 is formed from three 16-segment displayswhile a date display 868 is formed from two additional 7-segmentdisplays.

Turning back to FIGS. 4 a and 4 b, the ASIC is further connected to aninput port 702 by an I/O bus 704. This input port preferably is an octal3-state non-inverting/buffer/line driver/line receiver. This is anon-latching port. Address decoding and port enablement is provided by asingle external port and address decoder chip whose use is shared byoutput ports 668 and 662.

The keypad 38 is linked to an integrated key interface device 712. Theintegrated key interface device includes key interfacing, keydebouncing, and ESD suppression functions. This device is preferably anoctel CMOS switch debouncer with ESD protection for input pins up to 15kV. The keypad 38 includes four keys with raised buttons and tactileresponsiveness and one key without a raised button or tactileresponsiveness (i.e. a hidden key).

The integrated key interface device 712 outputs five signals 714 thatare provided to input port 702, the key interrupt generator 516, and toa key reset generator 716. Signals 714 include a separate signal foreach of the five keys. The signal for each key is low when that key isdepressed. The de-bounce duration provided by device 712 is at least 20ms and is 40 ms typically. The ESD suppression is rated at 15 kV usingthe human body model.

The key interrupt generator 516 includes an 8 input NAND gate that takesthe signal from each of the five keys and performs a NAND operation onthem, such that if any one of the keys is depressed (i.e. at least onelow input) a high signal will be output by the NAND gate and if no keyis depressed (i.e. no low input) a low signal will be output by the NANDgate. The output of the NAND gate is then passed to one input of a twoinput AND gate along with the reset signal 726 as the other input. As aresult if reset signal 726 is high (i.e. not asserted and at least onekey is depressed then a high asserted signal is received on line 514 bythe first interrupt input 512. If reset signal 726 is low (i.e.asserted) then any keyboard activity is blocked from asserting theinterrupt signal.

The key reset generator 716 provides an output signal 718 to an input ofthe OR logic circuitry 526. The key reset generator 716 receives lowsignals from the keys that are pressed and high signals from the keysthat are not being pressed. A series of OR gates are used to determineif all five keys are depressed (i.e. the four keys with raised buttonsand one key without a raised push button). The output of the OR gates ispassed through a 100 KΩ resistor and is linked to ground using a 0.1 μFcapacitor. This capacitor and resistor are used to suppress shortglitches that might be caused by static discharge from the externalworld via the keypad. Glitches shorter than about 10 milliseconds aresuppressed. The output signal is then fed to an inverter and then passedto one input of a two input AND gate. The other input of the AND gate isreset signal 726. The output of the AND gate is the key reset signal718. Which is passed on to the OR logic circuitry 526.

In addition to the input port 702 receiving key press signals 714 fromthe integrated keyboard interface 712, it also receives main battery lowinput signal 724 from power management circuitry 722 and a reset signal726 from battery fail detector 554. The signal 724 is asserted low andwhen asserted indicates that the main battery voltage is low. The resetsignal 726 is asserted low and when asserted indicates that the mainbattery is dead. The state of keypad is monitored by input port 702 andthe processor is expected to read the input port to determine which keywas pressed after receiving a keyboard interrupt.

The main source of power for the external device is a replaceable, AAcell main battery 732 of either the alkaline type or lithium type. Amain battery voltage signal 738 (VAA) is supplied to various componentsand modules as needed. Signal 738 is supplied to an input pin 544 of theanalog-to-digital converter that is included in the Processor IC.

The VAA signal 738 is also supplied to a switching type pulse widthmodulated DC-DC up-converter 734 that produces a boosted voltage signal736 (VCC) of a definable amount. In the present embodiment the definableamount is 3.45 volts +/−0.1 volt when powering a minimum load of 30 ohmsand when supplied with an input voltage of between about 1.1 volts and1.8 volts. The maximum ripple is 80 mV peak-to-peak. The start-upvoltage of the up-converter is no greater than 1.00 V when the startingload is less than 100 ohm at the output. The switching frequency isbetween 550 kHz and 750 kHz, nominally 600 kHz. However, under lightload, the up-converter utilizes burst mode, resulting in a wider noisespectrum. As VCC is generated using high frequency switching, theup-converter is preferably shielded from other components so as tominimize negative effects that might otherwise result, such as, forexample, on telemetry reception. In the present embodiment about 440 μFof capacitance is supplied to the VCC lines so as to provide some energystorage for the VCC signal.

The output signal 736 of the converter 734, VCC, is the main operatingpower for the external communication device though FIGS. 4 a and 4 b,explicitly depict only two of the modules to which voltage signal 736(VCC) is routed: (1) the external power on reset generator module 742,and (2) power management module 722.

A backup battery 752 is shown as supplying a voltage signal 754 VCOIN,to power management module 722 and is also passed to analog-to-digitalconverter input 546 for voltage monitoring. A preferred backup batteryis a 3.0 volt lithium battery having a 48 mAHr capacity. As noted above,the power management module outputs a signal 756 that supplies power tothe any circuits that are to remain powered by the backup battery whenthe main battery voltage signal 738, and thus boosted voltage signal736, falls below a usable level.

In the present embodiment the external SRAM 564 is powered by signal756. For data retention to occur the voltage supplied must be at least2.3 volts. In this embodiment signal 756 supplies a voltage of about 2.7to about 3.6 volts depending on whether or not the power is beingsupplied by the main battery or backup battery. The maximum operatingcurrent for signal 756 is about 1 mA.

Power management in the present embodiment is based on the powermanagement module 722, battery fail detector module 554, and externalpower on reset generator module 742. These modules are implemented usingthree primary integrated circuits along with other peripheral elements.The functions of the power management system include providing back-uppower for the on-board SRAM, providing proper power-up reset, andproviding adequate time for orderly system shut-down when the mainbattery is dead or removed.

The first chip is a 3 volt adjustable microprocessor supervisory ICwhich handles the functions performed by the power management module722. This chip monitors signal 736, VCC, and provides signal 736 as thesource for output signal 756 so long as VCC is about 2.7 volts orgreater and otherwise provides signal 754, VCOIN, as the source foroutput signal 756. When VCC rises above, about 2.90 volts, signal 736 isswitched back in as the source for output signal 756. The chip alsomonitors main battery voltage (VAA) and provides low power signal 724when VAA falls below a desired threshold that is settable by selectionof peripheral voltage dividing resistors. In the present embodiment theselected amount is about 1.1 volts. The low power output signal 724 isconnected to input port 702 where it can be monitored by the systemprocessor. The low power signal 724 is used by the Processor IC toprovide a low battery indication to the patient.

As noted above, the battery management IC also asserts an output signal762 when the backup battery is switched in as the source of VPOS. Thissignal is used to gate the chip select of the SRAM chips 564 so thatwhen the back up battery is maintaining the data in the SRAM chips, theSRAM chips cannot be accessed so as to protect the integrity of thedata. This asserted state also cuts the backup battery voltage to theprocessor using a PFET switch that opens line 754 so that it is notconnected to A/D input 546. This is done so that the backup battery isprotected from a potentially low impedance path to ground (e.g. the A/Dinput of the ASIC) that may occur when VCC is absent.

When the main battery is dead or removed, all memory access must becompleted before the back up battery on signal 762 is asserted. Theenergy storage capacitance on VCC serves this function by providing timefor system shutdown (enough time for completing selected shutdownactivities before VCC falls low enough that the back up battery onsignal 762 is asserted.

The second chip is a micro-power voltage monitor IC that is used as aprogrammable voltage detector and handles the functions performed by thebattery fail detector module 554. The programmability is determined bythe two voltage divider resistors. A hysterisis effect is used to ensurea good pulse and is obtained by use of a 500 kΩ resistor that bridgesthe input and output lines of the chip. This comparator monitors thevoltage signal 738 of the main battery. The output line of the chipprovides low reset signal 726. A second output signal for the batteryfail detect module is provided by passing signal 726 through an inverterto obtain a high reset signal 556. The threshold is set at about 1.0 Vin the present embodiment. The low reset output signal 726 is connectedto one of the inputs of input port 702. The high reset signal 556 isused as a power-fail interrupt signal to the processor. This interruptsignal is fed directly to the second external processor interrupt input552.

When the low reset signal 726 is asserted, the Processor disables theoutput ports, which in turn shut down all high power devices. This is toensure that the energy stored in the VCC storage capacitance is usedonly to support the orderly shutdown activities of the system in thecase when the AA battery is dead or removed. During shutdown mode anumber of conditions are set: (1) key presses no longer generate keyboard interrupts to the processor, (2) UART activity no longer generatesa UART interrupt to the processor, (3) the output ports, 668 and 662 aretri-stated, (4) the LCD is held in unselected and reset state, (5) thebacklight is disabled, (6) the vibrator is disabled, (7) the IrDA moduleis put in shutdown state, (8) the UART is put in shutdown state, and (9)a 150-ohm dummy load is disabled.

Since the high reset signal 556 is asserted by VAA falling below athreshold value (i.e. failure value for VAA) and since the failure ofVAA will cause voltage up conversion by module 734 to cease and sinceall high powered circuits have been shut down and since the back upbattery on signal is triggered by VCC failing and since VCC will bemaintained for some period of time by storage capacitance, there is atime lag between assertion of the high reset 556 and then assertion ofthe back up battery on signal 762. In this embodiment, the circuitry andstorage capacitance have been configured to provide a lag of at leastabout 100 ms. This amount of time has been selected as it is sufficientto enable all shut down activities by the processor to be completedprior to assertion of the back up battery on signal 762.

The third chip is an open drain reset IC and handles the functionsperformed by the external power-on reset generator 742. It monitors thevoltage signal 736, VCC. The chip produces an output pulse, or resetpulse, when the VCC voltage level transitions through a programmedthreshold voltage level. This reset pulse occurs when transitions arefrom low to high or from high to low. This reset pulse is routed throughan inverter and then to an input of an AND gate.

The input to the inverter is normally retained in a high state by a pullup resistor. However, the input to the inverter is brought low when thelow level reset pulse output by the chip occurs. A second input to theAND gate is provided by the low reset signal 726. This is done so as toonly pass the pulse on VCC rising but not the pulse on VCC falling. Fromthe AND gate the signal is routed to OR gate 526.

Output port 668 provides UART control signals 758 to the UART circuitryand provides a signal IrDA power down signal 760 to an IrDA module. TheUART control signals include a chip selector signal and a shutdownsignal. A preferred UART has an SPI™/Microwire™ interface and is capableof supporting RS-232 and IrDA links.

The UART supplies data on line 764 to an inverter 772 and from theinverter 772 to an IrDA transceiver module 780 on line 764′. The IrDAtransceiver module then transmits that data through an infrared carrierto a receiver in a second external device (not shown). Data that theIrDA device receives from the second external device through an infraredcarrier, is in turn passed to an inverter 774 on line 766′ and theinverter then sends the data on line 766 to the UART.

The data transfer rate through this port is fixed at 115.2 Kbit/s. Thisport complies with the IrDA 1.2 Low Power standard. Whenever externaldata is received by the IrDA transceiver, a UART interrupt is generatedby the UART IC. This interrupt, after passing through an inverter, isfed directly to the third external interrupt input of the processor.

The UART may be placed in a shutdown state to save power. When the UARTis in shutdown state, its oscillator is stopped. When the UART is set tobe taken out of shutdown state, it takes some time to start up theoscillator, and as such, application software is configured to provide aminimum of 100 ms for the UART to come out of shutdown state before realdata is transported using this port.

Output port 662 also provides an enable quiet mode signal 784 to NANDgate 642. The enable quiet mode signal 784 is used for quiet RF modecontrol. This signal is asserted high and is used when asserted todisable the EL backlight 806 and the vibrator 46. This signal isasserted during RF reception so that noise from these devices will notinterfere with RF reception.

The NAND gate 642 takes signals 784 (enable quiet mode) and 634 (RFreceive power) and produces an RF quiet signal 786 and provides it asinput to AND gates 792 and 794. As the enable quiet signal 784 and RFreceive power signals are both asserted high, the output of the NANDgate is low when both are asserted. The low RF quiet signal 786 disablesthe high noise devices stated above. It is also connected to VCC using a150 ohm dummy load. The purpose of this load is to force theup-converter to operate at the 600 kHz nominal switching frequency,instead of any other frequency or burst mode. This helps in reducingnoise during RF reception.

Output port 662 provides an output signal (not shown) to a 150 ohm dummyload that may be used to place a load on the AA battery during batteryvoltage measurement. This load is turned on by providing a high signalto it from the processor IC.

Output port 662 provides an enable LED signal 788 to AND gate 794. Theenable signal 788 is the backlight “on” signal and is asserted high.When asserted, this signal causes the backlight to be turned on unlessthe RF quiet signal is being asserted (i.e. low). AND gate 794 suppliesits output 802 as an input to a backlight driver 804 which in turnpowers an Electroluminescent (EL) backlight 806 which lights up the LCDdevice. A high RF quiet signal 786 enables the selection of thebacklight while a low RF quiet signal disables the selection of thebacklight, while the enable LED signal turns on and off the backlightwhen enabled. The backlight is controlled in this way because it is highcurrent/high noise device, and it is desirable to disable it during RFreception. When the system is not in an RF reception state, thebacklight is enabled regardless of the setting of enable quiet signal784 because RF receive power signal 634 is low.

The Electroluminescent (EL) backlight panel is used to illuminate theLCD in low light level conditions with a green light having about 0.15ft Lm brightness at 0.75 inches from the output of the LCD display. TheEL panel is driven by a DC-AC converter IC that boosts the voltagelevel. The DC-AC converter with the aid of an inductor to help generatethe boosted voltage level and a capacitor for setting the oscillatorfrequency boosts the voltage from VCC to a signal of about 140 VACpeak-to-peak at about 300 Hz.

Output port 662 provides and an enable vibrator signal 790 to AND gate792. The enable vibrator signal 790 is asserted high. When asserted thissignal turns the vibrator on unless the RF quiet signal 786 is beingasserted (i.e. low). AND gate 792 provides its output 812 as an input tothe vibrator device 46. The RF quiet signal 786 enables (logic high) anddisables (logic low) the selection of the vibrator, while the enablevibrator signal 790 turns on and off the vibrator when enabled. Thevibrator is controlled in this way because it is a high current/highnoise device, and it is desirable to disable it during RF reception.When the system is not in RF reception state, the vibrator is enabledregardless of the setting of the enable quiet signal 784 because the RFreceive power signal 634 is low.

The vibrator 46 is a DC vibration motor which is used as a secondaryalarm device. The preferred motor draws a current of about 60 mA and hasa nominal rpm of about 8100. The signal from AND gate 792 is used tocontrol an N-MOSFET transistor switch to supply the VCC signal to themotor.

As discussed above, a single processor IC is used in the externalcommunication device while two processor ICs are used in the ImplantableDevice. In this first preferred embodiment all three of these processorsare identical.

As it is preferred that the implantable device have a long implantedlife, and as the implantable device of the present embodiment does notuse rechargeable batteries, a low-power constraint is imposed on theprocessor IC. This low power constraint is three fold: (1) use of lowpower circuit elements and design, (2) use of electronic modules thatare capable of being put into low-power consuming states or non-powerconsuming states when not needed to perform specific functions, and (3)use of control hardware or software to put the modules in their reducedpower states and to pull them out of those states. The result is thatthe processor IC is designed and controlled to operate at an averagepower of less than about 30 μW. At a supply voltage of 2.9 Volts, thispower consumption turns into an average current of less than about 11μA. The entire implanted electronic system preferably draws an averageof less than about 32 μA. In this embodiment, the processor IC operateswith a voltage of between about 2.3 V and 3.6 V. To achieve desiredoverall power consumption for the implantable device, the processor ICis a custom designed CMOS device using 0.8 micron technology with thephysical construction of cell design utilizing small gates, drains, anddiffusion regions.

The core processor 912 design preferred in the present embodiment is aCMOS low power version of the INTEL 8086 processor with a minimizednumber of logic gates and enhanced timing so as to consume less power.The Core Processor includes ten additional instructions so that it issoftware compatible with the 80186 processor. It is a multiplexed busdevice having the 16 low order address bits, out of a total of 20address bits, multiplexed with the 16 data lines. De-multiplexing isachieved with on-chip latches so that the low order 16 address lines areavailable as outputs to the device. The four high order address linesand the bus high enable signal are not multiplexed. As noted above, theprocessor IC also integrates a number of modules and functions so as toreduce the power consumption as compared to using discrete componentsfor achieving the same functionality.

A SEEPROM interface 914 is provided within the processor IC forexchanging information with an off chip SEEPROM device. A two lineinterface is used to exchange data with the SEEPROM device and a powerline is also supplied from the processor IC to the SEEPROM so that itmay be selectively powered so as to reduce power consumption when accessto the SEEPROM is not needed. In the present embodiment, the SEEPROMassociated with each of the two processor ICs in the implantable devicehas a capacity of 32 kbytes while the two SEEPROMs used in the externalcommunication device have a capacity of 64 kbytes each. In the presentembodiment, the SEEPROM provides periodic acknowledgments when theSEEPROM is interacted with. A SEEPROM control register and a SEEPROMdata register are also provided. These two registers provide a bit thatsupplies power to the SEEPROM, a bit that provides an oscillating signalto the SEEPROM, a bit that provides data to be written to the SEEPROM,and a bit that can be read to pickup data that is being supplied by theSEEPROM.

The Boot ROM 916 is an on-chip read only memory that provides theinitial boot code for the CPU. The Boot ROM is 1 kbyte metal maskprogrammable ROM.

The address location of the beginning of the boot ROM 916 is isconsistent with the Intel 8086 specification for reset vectors. Whenreset occurs, the processor begins execution of the code found in ROMwhich is a program that loads further code from the SEEPROM locatedoff-chip. Further details on execution of the ROM code may be found inthe previously referenced U.S. patent application corresponding toDocket No. USP-1075-A.

A 16 kbyte section of static RAM (SRAM) 918 is provided within the ASIC.This space is used for stack, general variables, and core program spacesuch that most of the operational implantable device code and externalcommunication device code reside in this space.

The processor IC includes a memory decoder module 920 that is capable ofdecoding the 16 kbytes of internal SRAM and is also directly capable ofdecoding 512 Kbytes of external memory. The memory decoder containsBoolean logic gates to decode the 8086 address space for each individualbus transaction. The amount of externally addressable SRAM may beincreased by adding one or more additional bank select triggers such asby using the a processor IC output that is not being used for some otherfunction. For example, in the external device the output signal that isused to fire the pump mechanism may instead be used as a bank selectsignal as it is otherwise not being used. This provides the ability forthe external communication device to be able to decode 1 Mbyte, or more,of external SRAM. The memory decoder is further capable of decoding the1 Kbyte of internal ROM.

A low power crystal oscillator module 922 internal to the Processor ICis used in conjunction with the an external oscillator crystal and ashunting resistance to provide a stable 1.049100 MHz+/−500 Hz clocksource while drawing less than about 2 μA from a 2.2 V to 3.5 V supply.The circuit is intended to operate with a minimum frequency of 1.048576MHz crystal using a shunt resistance of about 20MΩ in the implantabledevice and about 2MΩ in the external communication device. The shuntcapacitance of the crystal is preferably no greater than 1.5 pF. Anexternal shunt resistor is provided in parallel to the clock crystalacross two external connectors of the ASIC to provide DC feedback to thecircuit. The amount of resistance is selected as a balance betweenoscillation start up and current consumption.

The timer module 924 is composed of the system clock generator andcircuits responsible for generating various timing signals. Theprocessor IC uses the (1.048576 MHz+500 Hz) external crystal to generatethe system clocks. Tolerance of the crystal oscillator is be better than+/−500 parts per million (ppm) including the drift due to aging, andtemperature induced variances within a range of −10° to 50° C.

The Timer Module 924 consists of a (A) system clock generator; (B) a CPUclock module; (C) a pulse stealer; (D) a clock enable register; (E) fourindependent timers (wake up 1, wake up 2, sleep, and one minute), and(f) a time-of-day timer that can be made to register time in subsecondintervals.

The system clock generator module, is a 20 bit ripple counter that hasthe ability to load a pattern into its lower 14 bits. This counter isused to provide the system clocks necessary for operation of all othermodules. In the present embodiment a pulse stealing technique is used tofine tune the oscillation frequency for all clock signals generated bythis module that have a frequency of about 8192 Hz or less.

The clock frequency of the CPU (i.e. the frequency of the CPU clock) maybe selected and the CPU clock made to stop by writing appropriate valuesto appropriate CPU clock registers. The frequency select circuitconsists of two registers and a synchronizing circuit. The synchronizingcircuit is used to ensure that narrow clock signals (i.e. glitches) areavoided when the frequency of the CPU Clock is changed.

A pulse stealer circuit is provided for precise system timing ofselected clock signals. In the present embodiment the pulse stealerfunction is applied to the clock signal that has a frequency that isjust slightly more than 8192 Hz target frequency as provided by thesystem clock generator. The pulse stealer circuit gives the ability toperiodically steal pulses from a selected clock signal to produce aclock signal of lower and more desirable average frequency. In thepresent embodiment the pulse stolen signal, is used to create all systemclocks that of lower frequency. In implementing pulse stealing for thepresent embodiment, the CPU loads a 16 bit value into two eight bitconfiguration registers. The timer whose signal is to be modified isused to cause a counter to count up from zero to the value loaded intothe registers at each time a comparator recognizes a match. After thecounter reaches the value specified in the registers, a single pulse isremoved from the output signal (stolen from the output signal) toprovide the modified output signal. Then the counting begins again fromzero and the process is repeated over and over so that a modified outputsignal, or pulse train, having a desired average frequency is generated.

A clock enable control register is provided so as to allow the CPU toselectively enable or disable the clock signals used by other modules.In the present embodiment these other modules include the first andsecond synchronous serial ports, the analog-to-digital converter, andthe insulin pump charging circuitry. Enablement/disablement for a givenmodule is “bit mapped” to the control register so that the controlregister may be used to “gate” these clocks on or off.

Four system timers are provided. These timers provide interrupts to theCPU at selected intervals. The internal logic of the first three ofthese timers is identical with the exception of the input clockfrequency and the number of bits to count to before causing aninterrupt. The interrupt interval for each timer is programmable by theCPU by writing an appropriate value to an appropriately sized controlregister associated with each timer. Once an interrupt interval iswritten into the timer by the CPU, interrupts will be continuouslygenerated by the timer without further intervention of the CPU. Thetimers continue to “run” independent of when or if the CPU services theinterrupts that they create. Thus, interrupts will continue to be“issued” at the same programmed interval, and will stay asserted if notserviced. The act of servicing the interrupt clears the interruptcondition. The CPU clears any pending interrupts by writing to theassociated control register.

The first of these timers is the first wake-up timer and it generates afirst wakeup signal that based on a 1 Hz input clock frequency and aprogrammed count value that is to be reached before generating itsinterrupt signal. Examples of the use of this timer in the presentembodiment include Watchdog monitoring and nominal RF reception andtransmission start times.

The second of these timers is the second wake-up timer and operates offan 8 Hz input clock frequency and is also programmable to count to aspecified value before generating its interrupt signal. Examples of theuse of this timer in the present embodiment include various uses withinthe external communication device, including spinning the pumping statusindicator on the display panel, IrDA timing for missing bytes andclosing the channel, beeping, and keyboard blink timing.

The third timer is the sleep timer which operates off a 1,024 Hz inputclock frequency and is programmable to count to a specified value beforegenerating its interrupt signal. An example of the use of this timer inthe present embodiment includes pump stroke charging and recharging.

The fourth timer is a one minute wake up timer and provides an interruptevery 60 seconds based on a 1 Hz input clock frequency. This counterprovides two functions: (1) it provides the seconds portion for the timeof day, and (2) it interrupts the CPU every 60 seconds. The principalpurpose for the CPU writing into this timer is to adjust the softwareperception of the second number within a minute. The register for thistimer does not hold the number to be counted to but instead holds thepresent count of the counter that continues to increment each seconduntil a count of 60 is reached and then it starts over. Examples of theuse of this timer in the present embodiment include counting elapsedminutes, performance of delivery calculations for pump strokes,determination of the present half hour, and one minute RF listening bythe external communication device.

In the present embodiment one register bit is controllable to indicatewhether RF reception is given priority over the charging of the pumpcircuit for noise considerations even though there may be some negativeimpact on power drain resulting from a need to partially recharge thepumping circuitry after a telemetry interruption. Toward this end, thepump clock itself is disabled whenever an RF receive power signal isasserted and the priority bit is set to give priority to RF reception.On the other hand, when this bit is oppositely set, by software, thenthe pump clock is allowed to remain on regardless of telemetry activity.As both telemetry operations and pumping operations are currentintensive, it may be desirable to avoid both systems operatingsimultaneous so as to reduce maximum current drain on the battery at anygiven instant in time.

A watchdog monitor circuit 928 is provided to ensure that detection andsystem reset will occur if the CPU ceases to properly executeinstructions. To achieve this, the watchdog monitor is configured toassert a system reset signal if an interrupt signal from the firstwake-up timer occurs twice without the CPU properly servicing thewatchdog monitor. In the present embodiment, the CPU resets the watchdogmonitor by two writes into the watchdog monitor. Data for the firstwrite has first pattern and data for the second write has a secondpattern that is different from the first pattern. To ensure that thesystem is operating properly at both the interrupt level and themainline code level, one of the two values is written by an interruptroutine while the other is written by the mainline code. Writes ofvalues other than the first pattern followed by the second pattern willreset the sequence that the Watchdog is expecting. The reset signalgenerated by the watchdog is brought out of the ASIC and back to theexternal reset input of the ASIC.

Following a system reset or power-on reset, the watchdog monitor is notactive. This allows the CPU time to perform initial configuration andhousekeeping. The watchdog is activated, or enabled, as soon as the CPUwrites any data pattern to a watchdog monitor register. Once enabled,the watchdog cannot be disabled until another CPU reset occurs. The ROMboot code activates the watchdog early on in its execution but sets thefirst wake up interval to a time sufficient for system configuration tooccur. When the watchdog causes a reset, a piezo signal is put out sothat an audio alarm will sound. This piezo signal remains on until theCPU re-activates the Watchdog.

The RF Module 930 in the processor IC consists of an (A.) RF timercircuit, (B.) a digital RF transmitter section that includes a QFAST® RFmodulation transmitter, (C.) an analog receive module, (D.) a digitalreceive section that includes a QFAST® RF modulation receiver, and (E) atime synchronization section.

The RF timer circuit provides clock signals used by the other portionsof the telemetry circuitry to provide a carrier signal for transmission,provide a signal for modulating the carrier, provide signals fordemodulating received signals, and the like. The primary signal timersignal is pulled from the system clock generator module. The generationand shut of the primary RF timer signal is controllable by hardware orsoftware based on values that are written into various registers whichenable signal generation when needed and power savings when not needed.The time synchronization module ensures that the concept of time as heldby the communication device and as held by the medical device aresufficiently close so as to enable RF communication to occur whilemaintaining transmission time and listening time of the RF hardware to aminimum. Further details on RF timing synchronization, autonomous andsoftware activation and deactivation of telemetry hardware componentsare provided in the above referenced US patent application correspondingto Docket No. USP-1077-A.

The telemetry system provides a half-duplex link between the implantabledevice and the external communication device using a carrier frequencyof about 250 kHz and a data signal having a frequency of about 8 kHz.The transmitter hardware uses the 8 kHz data signal to modulate thecarrier signal to generate signals that will be transmitted by theantenna. The receive hardware receives the modulated signal anddemodulates it to extract the 8 kHz data signal. Both the implantabledevice and the external communication device have transmit and receivecapabilities to allow two-way communication.

Most of the RF telemetry circuits necessary for communication betweenthe external communication device and the implantable device areimplemented in the processor IC. In order to minimize the digital noiseinterference that the processor IC might impart to the weak RF signalsthat are being received, a high-gain RF amplifier is implementedoff-chip. Also as discussed above, an RF antenna, that is used for bothtransmission and reception, and circuitry to select between receptionand transmission are implemented off chip. The remaining analog sectionsand all the digital demodulation circuits are implemented in theprocessor IC.

The RF module of the Processor IC outputs transmission signals fortransmission by the external antenna. It also provides a power signal tothe external amplifier and an RF receive power control signal that isused to switch between a transmission configuration and a receptionconfiguration. Both these signals are controllable by bit values placedinto registers so that power consumption may be minimized when componentoperation is not required. The RF module also receives input signalsfrom the external receiver hardware.

A Quadrature Fast Acquisition Spread Spectrum Technique (QFAST®) is usedas the modulation technique. QFAST® modulation is based on an OffsetQuadrature Phase Shift Keying (QPSK) modulation technique. In thistechnique, data generated by the CPU modulates clock signals at thecarrier frequency. As a result of quadrature modulation, in-phase andquadrature-phase components of the given data stream are generated.These two components are then applied to opposite ends of the externalantenna so that a combined signal is transmitted.

In QFAST®, data rate adaptability is accomplished through aspread-spectrum “coding gain” concept, with the spreading code being asimple clock. The modulation produced by the QFAST® modulator can bedemodulated in a manner which delivers both clock and data. All of theQFAST® modulation and demodulation circuits are digital and areincorporated into the processor IC.

The QFAST® technique provides a communication system with the followingattributes: (1) it extracts the clock from the received signal without aclock recovery loop; (2) it provides demodulation of data without phaseambiguity and without the requirement for synchronous demodulation; (3)it makes effective use of the available transmission bandwidth, (4) itresults in fast acquisition of the message signal; (5) it is relativelyimmune to the effects of highly dispersive and distorting propagationmedia; (6) it does not require regeneration of a phase-coherent localreplica at the receiver of the transmitted carrier; (7) it does notrequire resolution of ambiguity between the in-phase andquadrature-phase channels in the receiver; and (8) it does not exhibitdata phase ambiguity.

The transmitter section of the telemetry system receives byte wideparallel data packets from the CPU and then loads the data into aparallel-to-serial shift register. The serial data is then sent to theQFAST® RF modulation transmitter section to modulate two quadratureclock signal components each operating with a carrier frequency of about2¹⁸ Hz) and shifted in phase relative to each other by 90 degrees. Thetwo components are then delivered to opposite ends of the antenna. Aslong as there is data in the transmitter parallel-to-serial shiftregister, the RF transmitter remains activated. If the transmitterdoesn't have data available when the next byte is to be transmitted themessage is considered to have been completely transmitted and the CPUshuts off the transmitter circuitry so as to minimize continued powerdrain.

External to the processor IC, the received RF signal is amplified by ahigh gain receive amplifier. A bandpass filter is used to attenuateout-of-band components such as those due to AM radio stations. Theamplified RF signal then enters a mixer in the RF module of theprocessor IC and is converted to baseband using a two mixers, onein-phase mixer and one quadrature mixer both at the carrier frequency.The mixer outputs are the quadrature components of the baseband signals.An integrator & dump function in the RF module then removes the sumfrequency (2fc) and high frequency noise (i.e. acting as a low passfilter) from each of the two signal components. The processed signalsare then digitized using a comparator and passed to the demodulatorwhere the data and clock are recovered.

Further detail about QFAST® (Quadrature Fast Acquisition Spread SpectrumTechnique) may be found in U.S. Pat. No. 5,559,828, entitled TransmittedReference Spread Spectrum Communication Using a Single Carrier with TwoMutually Orthogonal Modulated Basis Vectors, by Armstrong, et al.

The ASIC also includes an interrupt handler 932. There are nineinterrupt sources. All interrupts except one are maskable. The onlynon-maskable interrupt is generated by the memory decoder as a result ofan invalid address detection. The interrupt handler module consists of acapture module for capturing interrupt conditions, a handling module,and a priority encoder module. Three of the nine interrupts may be usedfor external as well as internal interrupt sources, as for example bythe external communication device.

The capture module is used to capture the occurrence of an interruptibleevent. This module contains two sets of registers: an enable controlregister (under CPU control), and (2) the capture register. The enablecontrol register is bit mapped to each of the possible interrupt inputs.If the bit corresponding to an interrupt in this register is high theinterrupt is enabled and can cause the interrupt signal to the CPU to beasserted. When enabled, an interrupt condition signal sets a bit in thecapture register and a corresponding interrupt signal is asserted. Thebits in the Capture Register are de-asserted only by a system reset orindividually when a corresponding signal is asserted. The interruptsignals are passed to the interrupt processor module and combined withrespect to priority to provide a single interrupt to the 8086 CPUdelivered on the CPU's interrupt input line.

The handling module provides the necessary logic to accommodate the 8086double interrupt acknowledge cycle as well as daisy chaining theinterrupt signals to provide a priority for the highest level ofinterrupt in cases where multiple interrupts are pending simultaneously.When multiple interrupts are pending, the highest is serviced first.This is accomplished by asserting the output signal corresponding to thehighest pending interrupt during the second CPU interrupt acknowledgecycle. This signal serves two purposes. First it is fed back to thecapture module to clear the pending interrupt and second it is sent tothe priority encoder module for encoding the interrupt vector.

Only one of the inputs to the priority encoder module is asserted at atime. This module encodes the interrupt level number of the assertedinput and generates the appropriate interrupt vector value.

An analog-to-digital converter 934 (A/D) and associated signalmultiplexer system are provided to sample analog signals. The analogsignals for the implantable device include (1) battery voltage, and (2)the charge pump voltage. The analog multiplexer is used to select theanalog input signal that is to be provided to the A/D. An amplifier isused following the MUX to provide signal conditioning for the inputsignals. Bits are provided in a control register for selecting the MUXchannels, for enabling the MUX, for enabling the amplifier, enabling theanalog to digital converter, providing a conversion status indication,providing a begin conversion signal, and for supplying a clock signal tothe A/D converter.

The LCD Clock Driver consists of two input clocks (e.g. about 64 kHz(e.g. 216 Hz) and about 32 kHz (e.g. 215 Hz)), a MUX to select betweenthem and a bit and an AND gate to gate the clock on and off.

The Processor IC has an alarm driver and interface 938 that offersdirect control of a piezo buzzer alarm. The processor IC drives thealarm through a 2-wire interface. Software may be used to select one outof 128 frequencies ranging from about 64 Hz to about 8192 Hz. The toneduration and volume are also under software control. In thedual-processor implantable device, the monitor processor controls thebuzzer. The piezo buzzer logic consists of a register, a counter, andcompare functionality to provide a variable frequency to the piezobuzzer. The value in the register is compared to the value in thecounter. Each time the values are equal the driving signal toggles tothe next programmed signal. Additional logic circuitry is provided toallow volume control for the piezo buzzer. The outputs of each line areused externally as differential signals to the piezo buzzer. Thus withthis scheme, the piezo can sound different frequencies and the volume ofthe piezo buzzer can be controlled.

After a processor IC reset, the piezo is driven at about 1024 Hz. Thissignal is gated with the output of a register bit that is under controlof the CPU. The piezo signal is inhibited by this gate when the CPUwrites into the watchdog enable register.

The Processor IC has two Synchronous Serial Interface (SSI) ports 944and 942. Each interface provides full duplex serial communication portsthat operate at about 500 kHz. One of these ports is used forinter-processor communication in the dual processor implantable device.In the external communication device, one port is used for IR basedserial communications and the other is used as an interface for the LCDdisplay panel. Each interface port supplies both data and clock. Theclock driving the SSI may be enabled or disabled, thus controlling powerconsumption when the SSI is not needed. A control register is used toturn ON/OFF the SSI.

The RF communication between the implantable device and the externalcommunication device occurs in the form of messages (sometimes referredto as communication signals or packets) that are passed back and forthbetween the two devices. In this embodiment these messages have amulti-part format or protocol: (1) preamble, (2) frame sync, (3)telemetry identifier, and (4) data.

For communications from the implantable device to the externalcommunication device the preamble is a repeating pattern of “10”, i.e.10101010. This alternating pattern of ones and zeros is broadcast for8-bit times. This pattern is considered the standard preamble pattern.

For communications from the external communication device to theimplantable device, the preamble is either of the standard preamblepattern but applied for an extended number of bit times (e.g. 24, 48, or96) or is of an attention preamble pattern that is applied for,typically, even a longer extended number of bit times. The attentionpreamble pattern is formed of a repeated pattern of “110110 . . . 110”.In other embodiments, other attention preamble patterns may be used(e.g. repetitions of “011”, “110”, “001, “1011”, and the like).

The preamble, whether of the standard pattern or the attention pattern,is used so that the RF reception hardware can establish bitsynchronization (i.e. bit boundary recognition) of the incoming data.However, the attention preamble is further used to get and hold thereceiver's attention for a defined period of time. As long as theattention preamble is being received, the receiver's hardware will stayon and continue tracking the signal in anticipation of an incomingmessage.

The attention preamble is considered to be lost, or no longer beingreceived, when the receiver receives more than 2 inappropriate bitvalues during receipt of any 64-bits or when the frame sync pattern isreceived.

The attention preamble may be used when there is some uncertainty in thetime synchronization of the two devices. The extra length of theattention preamble allows the receiver's reception window to open alittle latter than anticipated and to still have the receiver pick upthe entire message. The extra length of the attention preamble allowsthe receiver's reception window to open earlier than anticipated, solong as a minimum number of bits are heard by the receiver during thetime its reception window is normally open, and still have thereceiver's attention locked onto the preamble and have the receiverremain on as long as the attention preamble is being received, plus alittle more, in anticipation of receiving a frame sync pattern.

In the present embodiment, frame sync may actually be considered bytesync (i.e. frames are bytes) and is a single byte of a selected patternand is used so the receiver can obtain byte boundaries for thetransmitted data. In the present embodiment, the selected pattern is“10110000

This comparison process continues so long as the receiver continues tolisten for an incoming message or until a valid frame sync pattern hasbeen received. If the receiver is continuing to listen beyond its normalreception window (i.e. listening period), due to the reception of anattention preamble, the listening will not stop immediately upon theattention preamble being lost. The comparison process for ascertainingthe receipt of frame sync continues for a number of bits after attentionpreamble is lost, even if the listening period has ended, as its lossmay be associated with the partial receipt of frame sync. Once framesync is received a valid frame sync signal is asserted.

In the present embodiment, the telemetry identifier (i.e. telemetry ID)is a 3-byte value that is used to ensure that only the intended receiverreceives a message. The value of all “1s” indicates a universal messagethat is to be received by all receivers, otherwise the telemetry ID mustbe agreed upon between the receiver and transmitter. A unique ID isprovided for each implantable device and each external communicationdevice during manufacturing. Only the external communication device cantransmit a message using the universal ID code. The telemetry IDs thatthe receiver will consider to be valid are the ID of the receiver or theuniversal ID. All other incoming bit patterns will be rejected with theresult that the receiver will be either turned off or will start againlooking for a valid frame sync pattern attention preamble.

If a valid telemetry ID is received, the receiver listens to theremaining portion of the message.

In the present embodiment, data is provided in an integer number ofbytes following the telemetry ID. In the present embodiment the firstbyte of the data indicates the message type. The first seven bits of thefirst byte is an operation code or op-code while the eighth bit iseither ignored or is set and interpreted as a sequence number (to bediscussed hereafter) dependent on whether or not the first seven bitscall for a sequence number or not. Each op-code, based on its nature, isfollowed by data in a defined number of bytes. The specific op-codeitself may dictate the number of bytes that follow or alternatively thespecific op-code may dictate that the number of bytes to follow may beextracted from the first byte or several bytes of information thatfollow it. In alternative embodiments, op-codes may have a differentlength, or not be used at all, the message length or message end may bedictated in other ways. Based on the op-code and potentially one or morebytes following it, the receiver knows exactly how many more bytes ofdata to listen for. After receiving those bytes, the receiver may beturned off to conserve power.

For some messages dealing with drug delivery, the data portion of themessage may include a bolus number. The bolus number is similar to thesequence number in that it is incremented by both the implantable deviceand external communication device under controlled conditions so as toreduce the possibility of bolus requests being delivered more than oncewhen duplicate requests may be made as a result of the externalcommunication device failing to receive a confirmation that a previousrequest was received. The bolus number may be a single bit number insome embodiments but in more preferred embodiments it is a multibitnumber (e.g. 2-bit, 4-bit, 7-bit, 1-byte, or 2-bytes) so that it cantake on more than two values thereby making it less likely that an errorwill escape detection due to received and expected numbers erroneouslymatching. The incrementing of the bolus number may occur within theexternal communication device when it receives confirmation that amessage was correctly received and it may be incremented by theimplantable device when it correctly receives a bolus request. As suchwhen a duplicate request for a bolus is received by the implantabledevice it can recognize that the expected and received bolus numbers donot match and that requested bolus is not a new request. As such theimplantable device can respond to the repeated request that the boluswas correctly received and delivered (with out performing a seconddelivery and without incrementing its expectation of what the next bolusnumber will be).

In the present embodiment, the data portion of the message ends with aone or 2-byte validation or error checking code (its type is dictated bythe op-code included with the message). The preferred error checkingcode of this embodiment is in the form of a cyclic redundancy code(CRC).

In the present embodiment, the telemetry system may loose bitsynchronization if insufficient bit transitions are received per unittime (e.g. if more than about 100 to 120-bit times lapse withoutreceiving a transition. In order to ensure that a sufficient number ofbit transitions occur, the data portion of the message, with theexception of the op-code is randomized prior to transmission and isde-randomized upon receipt.

In order to keep power requirements low in a preferred implementation,the external communication device and implantable device attempt tomaintain a common time base, transmissions are set to start at specifiedtimes, and reception windows are set for specified times and lengths. Inthis way, the receiver may remain in a powered down mode most of thetime and can turn on to listen for a potential incoming message at thespecified times for the specified lengths of time. If a message is foundto be incoming, the receiver stays on, otherwise it goes back to sleep(i.e. power down mode).

In the present embodiment time synchronization for telemetrycommunication is maintained using two techniques. The first techniqueperiodically determines the present difference in the concept of time(e.g. second boundaries) as held by the communication device and medicaldevice and the difference is used to reestablish synchronization of thetimers. In the present embodiment, reestablishment occurs on the part ofthe communication device each time it receives a valid communicationfrom the medical device.

The second technique determines a rate of drift that has occurredbetween the concept of time held by the communication device and that ofthe medical device. The determined rate of drift is used in combinationwith a determined lapse in time to estimate how much drift has occurred.This amount of drift is then used in shifting a listening start time ortransmission start time of a first one of the devices to match what isbelieved to be the potential transmission period or listening period ofa second one of the devices.

In the present embodiment, software may be downloaded from the externalcommunication device to the implantable device. The downloading ofsoftware may include the downloading of executable software as well asthe downloading of data structures that may be used by the executablesoftware.

In the present embodiment, a specific external communication device isconfigured/programmed to communicate substantively with only onespecific implantable device, that is in turn configured/programmed tocommunicate substantively with only the same specific externalcommunication device. An external communication device is capable ofretaining the telemetry ID of exactly one implantable device at a timeand an implantable device is capable of retaining the telemetry ID ofexactly one external communication device at a time. A small amount ofnon-substantive communication (i.e. communication that does not impactinsulin delivery) can occur between external communication devices andimplantable devices that are not linked (i.e. partnered or married) toone another (i.e. provided with each others telemetry IDs).

In the present embodiment, many different types of messages andresponses thereto can be written into the programs that control theimplantable device and the external communication device according tothe guidelines set forth above. These messages may be used for a numberof different purposes. For example, (1) they may be system levelmessages that are used for testing devices, for resetting devices, orfor establishing relationships between implantable devices and externalcommunication devices, (2) they may be alarm messages that are used toconvey alarm conditions or to clear alarm conditions, (3) they may bemiscellaneous messages that set various parameters or perform variousread operations, (4) they may be delivery messages that set deliveryamounts, read delivery status, or set parameters such as concentrationand pump stroke volume that may be required to appropriately controldelivery of the drug, (5) they may be data log messages that set datalog boundaries, read boundaries, or clear data logs, boundaries or readinformation from various data logs or supply information to those datalogs, (5) they may be refill messages that are related to amounts ofmaterial that are added to the reservoir periodically, (7) they may becompound messages that perform more than one function, or (8) they maybe error messages that request error condition status or supply errorcondition status.

Additional preferred features and aspects of a telemetry system areprovided in previously the referenced US Patent Applications thatcorrespond to Docket Nos. USP-1076-A, USP-1077-A, and USP-1079-A.

The External Communication Device (CD or ECD) is a hand-held device thatis used to program and communicate with an Implantable Device (ID). TheExternal Communication Device, of the present embodiment, includes thehardware features discussed herein above. The CD hardware and CDsoftware work together to provide the desired functionality for thesystem.

The hardware includes a display with an icon region and a dot matrixregion, a backlight for the display, a five-button keypad (one button ishidden), an alarm, a vibrator, and an IR device for serialcommunications with a second external device. The CD software ismenu-driven. The device operates from a replaceable 1.5 Volt AA battery.There is a backup battery that retains memory while the replaceablebattery is removed.

The dot matrix region is used to display the majority of the informationthat is provided to the user. This region, however, consumes morebattery power than the icon region, as such when the externalcommunication device is idle, the dot-matrix region is powered down toconserve energy. If the dot-matrix region is powered down, it is poweredback on once a key is pressed.

The various main menu options provided to the user in this embodimentare depicted in the block diagram of FIGS. 7 a and 7 b. Various set upmenu options accessible from the pump setup menu display of FIGS. 7 aand 7 b are depicted in the block diagram of FIGS. 8 a and 8 b. Variouspump set up II menu options accessible from the pump setup II display ofFIGS. 8 a and 8 b are depicted in the block diagram of FIGS. 9 a and 9b. Various supervisor functions/options that are accessible from theSupervisor display of FIGS. 7 a and 7 b are depicted in the blockdiagram of FIGS. 10 a and 10 b. The bolus delivery sequence of FIGS. 7 aand 7 b is further detailed in the block diagram of FIG. 11. Thecommunications sequence of FIGS. 7 a and 7 b is further detailed in FIG.12. In these Figures the ACT and SEL indications depict the keystrokenecessary to change from one display to the next. The up-arrow symboland down-arrow symbols indicate that parameter values within the menudisplay may be modified by pressing the UP key or the Down key.

One of the icons included in the icon region is the low-battery icon 858(FIG. 5) which is displayed when there is a low or depleted main orbackup battery. Another icon is the bell icon 860 (FIG. 5) which isturned on by the CD software when the external communication devicereceives a telemetry message from the implantable device indicating thatthe implantable device has detected one or more for the following: (1)implantable device inter-processor communications failure, (2)under-delivery, (3) over-delivery, (4) charge time too long, (5)post-fire voltage too high, (6) low implantable device battery, and (7)depleted implantable device battery. The bell icon is cleared by CDsoftware when all alarm conditions above have been cleared. The bellicon is displayed when the external communication device is showing the‘time and alarm’ screen.

Another icon is the reservoir level indicator icon 862 (FIG. 5). It iscomposed of 4 segments that provide a graphical indication as to thelevel of insulin in the implantable device reservoir. The CD softwaremaintains an estimate of the implantable device reservoir level. Theestimate is based on the refill amount indicated at the time of thelatest refill which is decremented by an estimate of the insulin thathas been delivered each day. The estimate of insulin delivered each dayis derived from the daily total log that records the number of pumpstrokes delivered each day. All segments of the reservoir level icon areset when the pump is refilled. The top-most segment of the reservoirlevel icon is cleared when the external communication device estimatesthat the reservoir is less than 75% full. The top two segments of thereservoir level icon are cleared when the external communication deviceestimates that the reservoir is less than 50% full. The top threesegments of the reservoir level icon are cleared when the externalcommunication device estimates that the reservoir is less than 25% full.All segments of the reservoir level icon are cleared when the externalcommunication device estimates that the reservoir is empty. Of course,in alternative embodiments a greater number, or lesser number ofindicators may be used to convey the reservoir level. The last iconcould be cleared when the reservoir level is not empty but instead hasreached a predefined “low level”. Alternatively, one or more of theelements could be controlled to blink when a low or empty reservoircondition exists.

Another icon is the Insulin Delivery Icon 864 (FIG. 5). This iconprovides a rotating display when the external communication deviceestimates that insulin delivery is in progress. The icon includes fourelements each forming a quarter of a pie shape. The rotationalappearance is provided by the CD software displaying alternatingpatterns that change every four seconds. When the external communicationdevice is simulating the delivery of a bolus, the pattern includes threedelivery segments on, and one off. When the external communicationdevice is simulating the delivery of a basal rate, the pattern includesone delivery segment on, three segments off. When the externalcommunication device is simulating no insulin delivery, all foursegments are on and as such, the rotational appearance is removed.

Four keys on the external communication device are provided with raisedpads and provide tactile responsiveness when depressed. These four keysare labeled SEL, ACT, UP, and DOWN. Some general rules apply to the useof these keys: (1) A SEL key press moves the current screen option tothe next screen option and does not change any parameter value, (2)Parameters that blink on the screen change by depressing the UP or DOWNkey one or more times or by holding down one of these keys, therebycausing accelerated scrolling to occur, (3) Once parameters are set tothe desired value, they are accepted by depressing the ACT key. A validACT keystroke is accompanied by a predefined ACT tone that is sounded bythe alarm buzzer. When the ACT key triggers a telemetry message to besent to the implantable device, upon completion of all telemetrytransactions, the external communication device emits a second ACT toneto indicate that telemetry is complete.

The backlight is activated by pressing the DOWN key from the ‘Time andMessage’ screen or the ‘time & alarm’ screen. The backlight isprogrammed to remain on for a selected period of time that may vary(e.g. 4 to 15 seconds) depending on the screen that is being displayedand/or the keys that have been pressed. For example, preprogrammed timeis 4 seconds following the display of the ‘time and message’ screen, the‘self test results’ screen, and the ‘24 hour basal total’ screen. Thetimer controlling automatic shut off is reset each time a key is pressedor held down so that the timing out of the backlight may be held off.

The external communication device includes two SEEPROMs, one is used tohold CD software and data and the other may contain an image of theimplantable device software. A third SEEPROM may be loaded into theexternal communication device for providing updated calibrationparameters and the like.

The external communication device uses the power management hardware todetermine the battery voltage level for the main battery and for thebackup battery.

The external communication device includes A/D hardware that is used inconjunction with CD software to read the main battery level every hour,and to read the backup battery level every day at noon. The CD softwarechecks the main low battery bit/signal 724 (FIG. 4 b) in the hardwareevery hour to detect a dead battery.

Upon battery removal, the external communication device writes data frominternal RAM to external RAM to prepare for the hardware to put themicroprocessor in the reset state. The data written from internal toexternal RAM includes parameters and data that are necessary for theexternal communication device to recover when the battery is replaced.This data is termed “external communication device recovery data.” Whenthe batteries are removed, the CD software powers down the LCD so thatthe screen goes blank and power is conserved for completion of thewriting operation. The CD software also computes a 16-bit RAM sum of theexternal communication device recovery data, and stores the RAM sum andits arithmetic inverse in external RAM. When the battery is replaced,external communication device performs boot up operations as describedherein later.

The external communication device communicates with the implantabledevice through messages passed by a RF telemetry link. When the externalcommunication device attempts to change parameters in the implantabledevice, the external communication device does not consider theparameter values to have been changed unless it receives the appropriatetelemetry response message from the implantable device. The CD softwareverifies the CRC of all the telemetry messages that are received. If thecalculated CRC does not match the CRC in the telemetry message, theexternal communication device updates a counter and otherwise ignoresthe receipt of the message. The CD software ignores all messages thatwere transmitted with the universal ID.

When transmitting most messages, sequence numbers are used. The sequencenumber provides a means to recover when the external communicationdevice does not receive a telemetry response from the implantabledevice. When the external communication device sends a telemetry messageand is expecting a response, if the response is not received, theexternal communication device has no way of knowing if the implantabledevice received the message and the external communication device missedthe response, or if the implantable device simply missed the message.The sequence number provides a means for the implantable device to knowwhether or not it has already received a message and thus whether or notit should act on a message. When the external communication deviceresends a message (as it did not get a response from the previousmessage), the external communication device uses the same sequencenumber it used when it initially sent the message. If the implantabledevice received the previous message, the implantable device knows notto duplicate its actions because the sequence number in the currentmessage is the same as the sequence number in the previous message. Inresponse to the resent message, the implantable device resends itsresponse packet using the same sequence number. This mechanism allowsfor the retransmission of a telemetry message without the implantabledevice acting on the message more than once.

The external communication device uses the sequence number parameter inthe sync response telemetry message as the sequence number for the nexttelemetry message. The external communication device uses the sequencenumber parameter in the interrogate response telemetry message as thesequence number for the next telemetry message after the user hasconfirmed the patient ID by pressing ACT on the ‘confirm implantabledevice serial number’ screen.

When the external communication device receives a valid response to atelemetry message, unless the response is an error message, the externalcommunication device changes the sequence number. In the presentembodiment the sequence number is a single bit and as such can take onthe values of “1” or “0”. When the Sequence Number is 0, it is changedto 1. Similarly, if the Sequence Number is 1, it is changed to 0.

The external communication device transmits to the implantable device oninbound time slots. The external communication device enables the RFreceiver every minute on the outbound time slot (e.g. on the secondboundary after the minute boundary). Following the transmission of atelemetry packet, the CD software in the external communication devicemay enable the RF receiver on the one-second boundary and may use alistening window size that is proportional to the length of thetransmitted preamble. Alternatively, the CD software may simply enablethe receiver and force it on for a time that is sufficient to capture anoutbound response. The RF timing system on the external communicationdevice is configured to synchronize its concept of seconds andsubseconds to those of the implantable device time upon receipt of eachtelemetry packet if the calculated CRC matches the CRC in the telemetrymessage, and the telemetry message is a valid response to an externalcommunication device message or a valid unsolicited message.

When the time between receptions is greater than 4 minutes and less than240 minutes, the external communication device computes a value for aone-minute RF drift variable and enters RF drift mode. If the timebetween receptions is not in this range, the external communicationdevice enters preamble mode.

When the external communication device is in RF drift mode, the CDsoftware updates a register, known as register B, by using a running RFdrift value. The register B value may also be updated based on apredefined value or based on the length of the preamble so as to starttransmission a desired amount of time prior to when the externalcommunication device believes the implantable device will open itsreception window. For example, the desired amount of time may be fromzero to up to one half the preamble length or more. The running RF driftvalue is initialized to zero or some other nominal value when drift modeis entered. When the external communication device is in RF drift mode,the running RF drift value is incremented by a one-minute drift valueeach minute. The one-minute drift value is obtained by consideration ofthe time between the previous two communications and the amount of driftthat was detected upon receipt of the latest transmission. Whenoperating in RF drift mode, the external communication device uses apreamble of 6 bytes. Further detail about register B and how theinformation in it is used to set reception times and transmission timesis provided in previously referenced US Patent Application No. (DocketNo. USP-1077-A)

If after the increment, the running RF drift value is out of range, theexternal communication device enters attention mode. When in attentionmode, the external communication device transmits using a two-secondpreamble of the attention pattern and initiates transmission using themaximum B Register value. This use of the maximum value in the Bregister is selected in hope of missing the reception window of theimplantable device when the transmission is first initiated and in thehope of catching the attention of the implantable device closer to theend of the transmission, thus minimizing the time that the implantabledevice's reception system is forced to remain powered up.

When the external communication device is in preamble mode, the CDsoftware maintains a running number of preamble bytes variable. Thisvariable is initially set to a desired minimum value (e.g. 4, 6, or 8bytes) and is incremented by a desired incremental value (e.g. 1-4 byte)each minute since the last communication occurred and is transmittedusing the attention preamble pattern. When the external communicationdevice is in preamble mode, the external communication device sets theregister B value so that the preamble is centered on the telemetrysecond boundary as determined by the external communication device. Whenin the preamble mode, and when the running number of preamble bytesexceeds a predefined maximum value (e.g. 256-512 bytes), the externalcommunication device enters attention mode.

In alternative embodiments, other decision-making processes may be usedto select between the use of preamble mode, RF drift mode or attentionmode. In fact, other modes may be defined such as a combined preambleand drift mode that widens the preamble length as time passes since theprevious communication and also uses a drift rate to reposition thetransmission window to keep it targeted to what the externalcommunication device believes is the most likely position of thereception window on the implantable device.

The external communication device initiates communication with theimplantable device by sending a telemetry message. If there is noresponse from the implantable device within a predefined time that isset by the CD software, or if the CRC of the received message does notmatch the CRC as calculated by the CD software, the CD software causesthe packet to be resent. The CD software sets the preamble of thissecond packet to be twice as long as that used by the former packet butno longer than two seconds. The second message may be termed a retrypacket. If the retry packet fails, the CD software initiates anotherretry but this time using a two-second preamble. If the externalcommunication device does not receive a response to the second retrymessage, or if the response CRC does not match the calculated CRC, theCD software reports a no response error.

When the no response error is acknowledged by the user, the CD softwaresets aside the original message and a sync message is prepared and sentusing an attention preamble that spans the gap that is believed to existbetween successive reception windows (e.g. 2 seconds). If a response isstill not received, the CD software may automatically (and without usernotification) resend the sync message again up to a predefined number oftimes (e.g. 0-3 times). If a response has not been received, the noresponse error is again displayed. This process is repeated each timethe error is cleared.

If a valid response is eventually received, and if the message was notan insulin delivery request, the CD software then retransmits theoriginal message using a sequence number as provided in the syncresponse message. If the original message was for an insulin request,the user may check the delivery logs that were updated in conjunctionwith the last sync response message to determine whether or not theprevious delivery was acted upon and thus whether or not it isappropriate to prepare a new delivery request.

If no valid response is received, the external communication device islocked out from performing any other operations other than continuedattempts to reestablish communication. After taking appropriate steps toincrease the likelihood of a successful communication without success,the user may elect to reset the external communication device andprogram it to send an interrogate message which will initially be sentwith a preamble that spans the entire period between successivereception windows that exist when the implantable device is in normalmode. If this fails to achieve communication, the CD softwareautomatically, and without user notification, resends the interrogatemessage using a preamble that spans the entire period between successivereception windows when the implantable device is in storage mode.

When telemetry is initiated by the external communication device, the CDsoftware controls the external communication device to display the“transmitting to implantable device” screen so as to present the userwith a positive visual feedback that the external communication deviceis attempting to communicate the required telemetry commands.

If a response is received from the implantable device, the acceptabilityof the response is verified by CD software. If the response isincorrect, or the response is not detected, the above noted no responseerror is asserted after making the multiple initial attempts toestablish communication.

The external communication device recognizes a number of different typesof alarms and conditions. The various alarms and conditions are definedwith an alarm description, siren, alarm origin, and a display definitionfor three message areas on the dot matrix portion of the display. Thesiren indicates whether a yellow (Y) or blue (B) siren will be used whenthe alarm is active. The alarm origin indicates if the alarm isgenerated from a condition associated with the external communicationdevice or with the implantable device. An alarm code is specified for anumber of the potential alarm conditions. This is a unique number foreach alarm condition and is used to identify the alarm in the error logand on the display.

When the CD software recognizes an alarm condition originating from theimplantable device (received through telemetry), the CD softwareactivates a siren and displays a message on the dot matrix display. Themessage is displayed on the ‘time & alarm’ screen and the siren isinitiated immediately. The CD software cancels any active userinteractions. When the alarm is acknowledged by the user, (e.g. bypressing the SEL key followed by the ACT key), the CD software preparesa telemetry message to clear the active implantable device alarm and torequest an update of the error log. If multiple alarms are present, theyare presented one at a time in prioritized order and each one may beacknowledged, cleared, and the log updated according to the above notedprocess. After clearing the alarms, the processing that was in progresswhen the alarm conditions are asserted is allowed to continue in mostcases. In alternative embodiments, multiple alarm conditions may bedisplayed simultaneously and cleared simultaneously, or they mayreviewed in turn and then cleared simultaneously.

The purpose of alarm conditions is to get the user's attention as soonas possible under most conditions. Exceptions are stop pump, suspendpump, and implantable device auto off as these conditions are systemstates that are cleared when the user presses SEL and ACT. As the systemgenerally attempts to initiate alarm conditions on the externalcommunication device first to save power in the implantable device,since telemetry transmissions are less power consumptive than buzzeractivations, minimizing the duration of the alarm condition on theexternal communication device result in reducing the possibility of theImplantable Device alarming internally.

Reassertion of implantable device alarms are dependent on the alarmcondition not being removed (i.e. the condition has not been clearedthough its existence was previously acknowledged) by the timereassertion is to occur and on the implantable device communicating theerror to the external communication device. Reassertion results in thealarm condition again being displayed on the LCD and the siren beingactivated and requiring that the use acknowledge the alarm.

The CD software handles external communication device alarms in much thesame manner that it handles implantable device alarm conditions with theexception that telemetry packets need not be prepared and sent toacknowledge the alarm conditions. Reassertion of external communicationdevice alarm conditions is similar to that for reassertion ofImplantable Device alarm conditions in that they also result in a newalarm condition on the external communication device which the user mustacknowledge. The exceptions to this rule are temporary basal rate,delivering diagnostic rate, and delivering priming bolus which aresystem states that require the external communication device to beepperiodically. The following Table depicts the various alarm conditionsthat are recognized in the present embodiment in order of priority.Alarm Conditions P Alarm Description O S Messages 0-1 M2AC 1MAIN_BATTERY_DEPLETED CD Y CD - DEPLETED BATT 2 MAIN_BATTERY_LOW CD YCD - LOW BATTERY 3 BACK_UP_BATTERY_LOW CD Y CD - NEEDS SERVICE 4NO_RESPONSE_EVENT CD Y TELEMETRY - COMM 3 ERROR 5 ID_DEAD_BATTERY ID YPUMP STOPPED 6 6 ID_EMPTY_RESERVOIR ID Y EMPTY - RESERVOIR 7ID_OVER_DELIVERY_ERROR_BIT ID Y PUMP STOPPED 4 8 ID_UNDER_DELIVERY_ERRORID Y PUMP STOPPED 5 9 ID_IP_COMM_ERROR ID Y PUMP STOPPED 1 10ID_CHARGE_TIME_TOO_LONG ID Y PUMP STOPPED 2 11ID_POST_FIRE_VOLTAGE_TOO_HIGH ID Y PUMP STOPPED 3 12ID_AUTO_OFF_INTERVAL_EXCEEDED ID Y AUTO OFF - PUMP SUSPENDED 13ID_LOW_RESERVOIR ID Y LOW - RESERVOIR 14 ID_LOW_BATTERY ID Y PUMP - LOWBATTERY 15 APPLICATION_VERSION_ERROR_EVENT CD Y PUMP - ERROR 0 16TELEMETRY_VERSION_ERROR_EVENT CD Y PUMP - ERROR 1 17 INVALID CD Y PUMP -ERROR 40 CONCENTRATION 18 INVALID STROKE CD Y PUMP - ERROR 41 VOLUME 19EXCLUSION_LIST_FULL CD Y TELEMETRY - COMM 20 ERROR 20 STOP_PUMP_ALARM CDB PUMP STOPPED 21 SUSPEND_ALARM CD B PUMP SUSPENDED 22 DOWNLOAD COMPLETECD Y DOWNLOAD - COMPLETE 23 DOWNLOAD_FAILURE CD Y TELEMETRY - COMM 27ERROR 24 UNINITIALIZED_CD_EVENT CD Y CD - NOT INITIALIZED 25ID_RESET_TO_DEFAULTS CD Y PUMP - RESET 26 CHECK_PUMP_STATUS CD Y CHECK -PUMP STATUS 27 HOURLY_MAXIMUM_EVENT CD Y HOURLY MAX - EXCEEDED 27ID_INITIALIZED CD Y PUMP - INITIALIZED 29 ID_SELF_TEST_ERROR CD Y PUMP -SELF TEST FAIL 30 AUTO_OFF_ALARM CD Y AUTO OFF - IN 5 MINWhereP = Priority,O = Origin,S = Siren, andM2AC = Message 2 Alarm Code

When the text in Messages 0-1 do uniquely define an alarm condition, anAlarm Code is additionally displayed as a numeral that indicates thespecific cause of the alarm condition.

The CD software records all external communication device alarms in theexternal communication device system events log.

If the low battery voltage signal is active, the CD software initiates aCD battery low alarm. A low battery message will persist on the “Timeand Message” screen until the battery has been replaced. In alternativeembodiments, instead of constantly displaying this condition and thuskeeping the dot matrix powered continuously, the existence of thiscondition may only be displayed for limited times. For example, it maybe displayed when the user first interacts with the device after a timeout period, or it may also be displayed after various commands aregiven. If the external communication device is not recognizing a deadbattery condition, the CD software initiates a low battery conditioncheck every hour. When the low battery condition is detected, the CDsoftware logs the event.

If the dead battery voltage signal is active, the CD software initiatesa CD Main Battery Depleted alarm. The CD software causes a depletedbattery message to persist on the “Time and Message” screen until thebattery is replaced. When the depleted main battery condition isdetected, the CD software logs the event.

The CD software causes the voltage of the backup battery to be checkedevery day. If the battery voltage is too low, then the externalcommunication device needs to be refurbished. The CD software alsochecks for the depleted backup battery condition every day. When thedepleted backup battery condition is detected, the CD software causesthe depleted backup battery message to be displayed on the ‘time andmessage’ screen and logs the event. Though the user may clear the alarm,the depleted backup battery message continues to be displayed on the‘Time and Message’ screen until refurbishing occurs.

When an alarm is displayed, the external communication device ‘Time andAlarm’ screen is active, and the user must clear the display. In thepresent embodiment, this is accomplished by pressing the SEL key andthen the ACT key for alarms generated by the external communicationdevice. This is initiated by pressing the SEL key and then the ACT keyfor alarms generated by the Implantable Device.

When an implantable device alarm is cleared by the user, the CD softwareprepares a clear alarm telemetry message that is transmitted to theimplantable device. Upon receipt of the response, the CD software clearsthe active alarm condition that is displayed to the user. The CDsoftware also re-prioritizes its alarm conditions. If there are anyoutstanding errors, the CD software causes the one with the highestpriority to be displayed and the external communication device remainsin an error state. The process of displaying, clearing, andreprioritizing continues until there are no more outstanding errors. Ifthe alarm was detected during a telemetry transaction, the CD softwareresumes the telemetry transaction. However, if the alarm notificationfrom the Implantable Device to the external communication device occursas a result of one of the messages transmitted as part of the externalcommunication device to Implantable Device initialization process (i.e.marrying process) the initialization process is not resumed but must berestarted beginning with the Interrogate Message.

The CD software is configured to periodically write to the watchdoghardware registers. If the system watchdog requirements are not met, awatchdog alarm is triggered and the watchdog tone is enabled by thehardware. An infinite loop at mainline or an infinite loop at interruptlevel will cause the watchdog to reset the processor IC as the CDsoftware must write one of a 0x5B or a 0A5 to the watchdog register inmainline code and the other at interrupt level.

Sirens (either audio alarm or vibrational alarm) are activated by the CDsoftware when the external communication device detects an alarmcondition. Sirens are deactivated by CD software when the alarmcondition is cleared by the user. There are two types of sirens, yellowsirens and blue sirens. For yellow sirens, when the alarm type is set to‘vibrator,’ the CD software activates the vibrator for 3 seconds everyminute while the yellow siren is active. When the alarm type is not setto ‘vibrator,’ the CD software initiates a high beep tone 6 times with250 ms between each beep, every minute while the yellow siren is active.If the yellow siren is active for more than 30 minutes, (user does notacknowledge the alarm within 30 minutes), the CD software sets the alarmtype to high and initiates an alert tone every minute until the yellowsiren is deactivated. If the alarm type was set to vibrator prior tocrossing the 30-minute threshold, the alarm type is converted to high(i.e. loud audio) at the 30-minute threshold.

For the blue sirens, when the external communication device alarm typeis set to ‘vibrator,’ the CD software will activate the vibrator for 3seconds every 30 minutes while the blue siren is active. When theexternal communication device alarm type is not set to ‘vibrator,’ theCD software initiates a high beep tone 3 times with 250 ms between eachbeep, every 30 minutes while the blue siren is active.

The frequency and durations for the types of sounds generated by thetone generator are listed in the following table. Tone Frequencies ToneDuration Frequency Repeat Number ACT Tone 125 ms 516 Hz 1 High Beep Tone250 ms 941 Hz 1 Audio Bolus Tone 1 250 ms 516 Hz 1 Audio Bolus Tone 2250 ms 592 Hz 1 Audio Bolus Tone 3 250 ms 667 Hz 1 Audio Bolus Tone 4250 ms 696 Hz 1 Double Audio 250 ms 516 Hz 2 with 125 ms Bolus Tone 1delay between Double Audio 250 ms 592 Hz 2 with 125 ms Bolus Tone 2delay between Double Audio 250 ms 667 Hz 2 with 125 ms Bolus Tone 3delay between Double Audio 250 ms 696 Hz 2 with 125 ms Bolus Tone 4delay between No Action Tone 500 ms 380 Hz 1 Alert Tone 250 ms each 941Hz 6 followed by 516 Hz Alarm Tone 250 ms each 941 Hz 50  followed by516 Hz End Bolus Tone 250 ms 444 Hz 1

ROM boot code within the processor IC loads the external communicationdevice bootloader code from the SEEPROM and factory defined parameters.When the external communication device boots, CD software reads thepower down recovery data from external RAM and calculates the power downrecovery data checksum by performing a 16-bit sum with the carry of thedata. The CD software calculates the power down recovery data checksuminverse by performing an arithmetic inverse of the power down recoverydata checksum.

If the calculated power down recovery data checksum matches the value inexternal RAM, and if the calculated power down recovery data checksuminverse matches the value in external RAM, the bootloader code copiesthe CD software (i.e. application code) from external RAM into internalRAM.

If the calculated checksum or checksum inverse do not match the valuesin external RAM, the external communication device loads the applicationcode into external RAM from the SEEPROM. Once application code isresident in external memory, the internal portion of the code is copiedfrom external memory to internal memory.

If the select, up, down, and activate keys are all depressed atpower-up, the external communication device loads the application codeinto external RAM from the SEEPROM. Once the application code isresident in memory, the internal code portion is copied from externalmemory to internal memory.

When loading of the software is complete, the external communicationdevice application code is started by an inter-segment jump to the mainexternal RAM initialization address location.

Before performing conversions between insulin units and pump strokes,the CD software compares the stroke volume variable to its complimentform. If they do not agree, the CD software causes the externalcommunication device to be reset.

Before performing conversions, the CD software compares the insulinconcentration variable to its compliment form. If they do not agree, theCD software causes the external communication device to reset.

The CD software causes the external communication device to displayinsulin quantities to the user based on one more selected predefinedunits of resolution (e.g. 0.2 units for bolus quantities and 0.1 unitsfor basal quantities). However, most computations performed by both theimplantable device and the external communication device involve pumpstroke volumes. In the present embodiment, the pump stroke volume isnominally 0.5 μL actually pump stroke volume may vary from this amount.When using U 400 insulin with a nominal stroke volume of 0.5 μL adispensing resolution of nominally 0.2 units of insulin results.However, since the stroke volume may vary, the actual dispensingresolution may also vary. As such programming and interfacing betweenthe user and device occur in increments that are not necessarily integervalues of the pump stroke volume.

The CD software converts units to pump strokes based on the insulinconcentration and the stroke volume:${PumpStrokes} = \frac{{{Units}(U)}*1000\left( \frac{uL}{mL} \right)}{{{Concentration}\left( \frac{U}{L} \right)} \cdot {{StrokeVolume}({uL})}}$

The CD software converts pump strokes to units based on the insulinconcentration and the stroke volume:${Units} = {\frac{{{Concentration}\left( \frac{U}{mL} \right)} \cdot {{StrokeVolume}({uL})}}{1000\left( \frac{uL}{mL} \right)} \times {Pump}\quad{Strokes}}$

For display, the CD software rounds to units to the nearest 0.2 unitboundary for each Bolus and to 0.1 units for basal rates. All logshowever, are maintained in pump stroke units and then converted toappropriate insulin units when displayed

Suspend mode is a mode where the implantable device is programmed todeliver at a rate of one pump stroke an hour. The rate is clinicallyinsignificant and serves to prevent catheter blockage. Suspend mode isenabled by the CD software from the ‘suspend pump’ screen. When suspendmode is entered, the CD software prepares a telemetry message fortransmission to the implantable device to set its delivery mode to“suspend”. When the implantable device is in suspend mode, the CDsoftware causes the display the alarm screen to display the “pumpsuspended” alarm as active. When the “pump suspended” alarm condition iscleared, the CD software prepares a message for transmission to theimplantable device to set the implantable device delivery mode to“normal”. When the “pump_suspended” alarm condition is cleared, the CDsoftware determines if a bolus was interrupted when suspend mode wasentered. If so, it updates the bolus history log to indicate the amountof the bolus that was delivered. The CD software only provides access tothe Supervisor Menu Screens while the pump is in suspend mode. A blockdiagram of the supervisor menu screens and options is provided in FIG.10.

An audio bolus option is provided that enables the user to safely andreliably deliver a bolus without looking at the display. The CD softwareenables and disables this option from the Audio Bolus Screen in thesetup menu. A block diagram of the set up menu screens and options isprovided in FIG. 8. When audio bolus status is ON, the CD softwareenables the user to initiate delivery of a bolus by pressing the uparrow key from the ‘time and message’ screen as well as the ‘time’screen. The CD software causes the external communication device to beepand the bolus increment to be displayed as when the up key is firstdepressed. The CD software provides no scrolling effect when a key isheld down. The CD software increases the amount displayed by the bolusincrement amount and beeps with each subsequent press of the up key.

In order to audibly distinguish bolus increments, when using the audiobolus feature, the CD software provides a single tone beep when theincrement amount is set to 0.4 U, and a double tone beep when theincrement value is set to 0.8 U. Of course, in alternative embodimentsother incremental amounts may be used and different audio signals usedto indicate which is active and what increments have been made. In onesuch alternative, the CD software could control an appropriatelyconfigured external communication device to speak to the user. Inanother such alternative, the CD software could provide voicerecognition features to an appropriately configured the externalcommunication device so that commands could be spoken instead of keyedin.

In the present embodiment, the CD software facilitates counting theaudio bolus increments by varying the audio tones for the beeps thataccompany the Up arrow key presses. The CD software provides fourfrequencies that are used in a repeating sequence as the UP arrow key isrepeatedly pressed until the desired bolus amount is selected. Duringthe programming of the audio bolus amount, the CD software interprets apressing of the down key and sel keys to cancel the bolus. When thedesired bolus amount has been programmed (and is displayed), the usermay activate it by pressing the act key. When the act key is pressed andthe amount is not zero, the CD software causes the externalcommunication device to play back the beep sequence generated duringbolus amount selection. The CD software interprets a subsequent pressingof the ACT key, as confirmation that the user wants to have theprogrammed amount delivered and as such displays the ‘immediate bolusconfirmation’ screen. The CD software prepares a bolus delivery messagefor transmission to the implantable device after the user confirms thebolus amount selection by pressing the ACT key again. To cancel thedelivery of the bolus after an amount has been set or while theconfirmation screen is being displayed, the user may either allow the CDsoftware to time-out and return to the ‘time and message’ screen or theuser may press any key other than the act key.

When the delivery of an audio bolus is canceled, the CD software causesthe ‘time and message’ screen to be displayed and causes a no actiontone to be emitted. The CD software stores the audio bolus status andaudio bolus increment parameters in the external communication devicedata block.

The CD software enables the external communication device to requestdelivery of three types of boluses. These are the normal bolus, thesquare wave bolus and the dual-phase bolus.

The normal bolus (immediate bolus or phase 1 bolus) gives the user theoption to program a bolus amount in units of insulin. The insulin unitsrequested for delivery are translated by the external communicationdevice to an integer number of pump strokes, a telemetry message isprepared and transmitted to the implantable device which then deliversthe amount.

The square wave bolus (phase 2 bolus) is programmed as an amount inunits and a duration. The CD software translates the amount into a rate,a telemetry message is prepared and transmitted to the ImplantableDevice which then delivers insulin the computed rate for the givenduration.

The dual phase bolus (two-phase bolus) is a combination of the normalbolus and the square wave bolus. The user programs a phase-one amount, aphase-two amount, and a phase-two duration into the CD software. Thephase one amount is treated like a normal bolus. The phase-two amountand duration are treated like a square wave. A telemetry message isprepared and transmitted to the implantable device which is thenprogrammed to deliver the two components of the bolus.

When a parameter called variable bolus status is set to OFF, the onlytype of bolus delivery that can be programmed is the normal bolus. TheCD software presents the user with a ‘set bolus amount’ screen that theuser may interact with to program a normal bolus. The CD software allowsthe user to increment up and down through allowable bolus amounts byusing the up and down keys. The maximum amount that can be scrolled tois equal to programmable maximum bolus quantity. The CD softwaredisplays the ‘immediate bolus confirmation’ screen when the userdepresses the act key (so long as the bolus amount indicated is notzero). When the act key is pressed again, the CD software prepares abolus delivery request message for transmission to the implantabledevice.

The CD software allows a Square Wave bolus to be programmed when thevariable bolus status is set ON. From the set bolus display, the CDsoftware enables the user to select, intra alia, a square wave bolus.Once selected, the CD software shows the user a ‘set bolus amount’screen with portion of the display blinking indicating that an amountmay be entered. A desired bolus amount may be entered by the user usingthe up and down keys. The CD software limits the amount that may beentered to the predefined maximum bolus amount. After entering theamount and pressing the act key, the CD software displays a blinkingregion for setting bolus duration. After entering the desired durationand depressing the act key, the CD software displays a blinking screenthat shows the details of the extended bolus that has been programmed(i.e. ‘Extended Bolus Confirmation’ screen). If the user agrees that adelivery having the indicated details should be made, the CD softwareinitiates a telemetry delivery request message when the act key ispressed again

The CD software also allows a dual bolus to be programmed when thevariable bolus status is set on and the bolus delivery type is set todual. In programming the bolus, three screens are presented to the userone after the other: (1) the ‘set bolus amount’ screen is displayed forentry of the immediate portion of the bolus, (2) the ‘set phase 2amount’ is displayed for entry of the square wave portion of the bolus,and (3) the ‘set phase 2 duration’ screen is displayed for entry of thesquare wave duration. The user progresses through these screens byentering the desired amount as each screen is displayed and then hittingthe act key. After the act key is depressed while the ‘set phase 2duration’ screen is displayed, a flashing the ‘Extended BolusConfirmation’ screen is shown. If the user agrees that a delivery havingthe indicated details should be made, the CD software initiates atelemetry delivery request message when the act key is pressed again.The CD software limits the total bolus amount programmed for thecombination of the Immediate and the phase-2 boluses to be no more thanthe predefined maximum bolus amount.

For each of the above three cases, bolus delivery is initiated by the CDsoftware preparing and initiating a deliver bolus, read totals telemetrypacket. The CD software calculates the number of pumps to be deliveredin the immediate bolus based on the amount programmed with the resultrounded to the nearest integral number of pump strokes. The CD softwarealso uses the phase-2 amount and duration to calculate a phase-2delivery rate in pump strokes per minute. The calculated amount, rateand duration are passed to the implantable device for delivery in theabove noted delivery request message. When the CD software estimatesthat a bolus delivery is in progress, the rotating delivery status iconindicates that a delivery is in progress and ‘time and message’ screenprovides a delivering bolus message and an estimate of the amountdelivered.

The CD software, estimates the amount delivered in the immediate phaseof a bolus to be one pump stroke during each predefined interval of time(e.g. 2-4 seconds). Incrementing starts on the minute followingcompletion of bolus programming.

The CD software disables the ‘set maximums’ screen during delivery of abolus. Also when the estimate of the immediate amount delivered is lessthan the programmed amount, the ‘set bolus amount’ screen is alsodisabled. When the estimate of the immediate amount delivered equals theprogrammed amount, the ‘set bolus amount’ screen is enabled. When theestimated delivery of the combined amounts (immediate and extended) iscomplete the CD software causes the external communication device toemit an end of bolus tone. The CD software inhibits entry of anadditional extended bolus delivery when an extended bolus is already inprogress. The CD software locks out all bolus delivery screens duringthe delivery of an immediate bolus, diagnostic rate, or primary bolus.

As noted above, a variable bolus rate option in provided. A variablebolus status parameter is also provided that is indicative of whetherthe user has the capability of entering delivery instructions for allthree bolus types or only the immediate type. When the option is on,bolus delivery includes a screen to choose the bolus type. When theoption is off, the user can only program normal boluses. In eitherevent, the CD software provides the user with access to those screensand options that are available to him/her and removes access/display ofthose screens that provide programming capability for the unavailableoptions.

The CD software provides a ‘variable bolus’ screen that may be used toset the variable bolus status parameter to on and off for enabling theprogramming of square wave boluses and dual wave boluses. The CDsoftware causes the variable bolus status parameter to be stored in theexternal communication device data block.

The CD software provides the user with the capability of displaying thetime of delivery and the amount for each of the most recent 512 boluses.Priming boluses are displayed along with variable and audio boluses. TheCD software provides a ‘bolus history’ screen that display the mostrecently delivered or programmed bolus. The older entries in the bolushistory log are displayed when the down arrow is pressed. Newer entriesin the bolus history log are displayed when the up arrow is pressed. Theup arrow is ignored when the external communication device is displayingthe most recent bolus. The CD software ignores any down key presses whenthe external communication device is displaying the oldest log entry.When a bolus is programmed, the CD software sets the bolus statusparameter to ‘programmed’. The CD software updates the bolus history logwhen the response to the deliver bolus read totals telemetry packet isreceived. The CD software blanks a bolus status parameter when aresponse to a deliver bolus read totals telemetry packet indicates thatthe amount displayed for the most recently programmed bolus wasdelivered.

The CD software provides the user with the ability to display the totalamount of insulin delivered during each of the most recent 120 days on a‘daily totals’ screen. The amount for the current day is only accurateup through the delivery of the previous bolus, not the current bolus, orthe last bolus. The CD software retains the total basal delivery and thetotal bolus delivery as separate amounts for each day in the dailytotals log. The CD software displays older entries in the daily totallog when the down arrow is pressed. The CD software displays newerentries in the daily total log when the up arrow is pressed. The CDsoftware ignores Up key presses when the most recent entry in the dailytotal log is displayed and ignores the down key presses when the oldestdaily total log entry is displayed. The CD software updates the DailyTotals log using the current day's total and yesterday's total from theTM message, when a response to the Deliver Bolus, Read Totals telemetrypacket is received. The CD software maintains a pointer that indicates“today” in the daily total log. The CD software increments this pointerat midnight. When the CD software increments the pointer indicating“today”, the daily total for the new day is set to dashes.

The CD software provides the user with the ability to display thecontents of the external communication device event log on a ‘externalcommunication device ‘clinical history’ screen. The most recent eventcode for the most recently logged external communication device event isdisplayed on the screen. The CD software displays older entries in theexternal communication device event log when the down arrow is pressedand newer entries in the external communication device event log whenthe up arrow is pressed. The CD software ignores up arrow key presseswhen the external communication device is displaying the most recententry in the external communication device event log and ignores downkey presses when the external communication device is displaying theoldest entry in the external communication device event log. The CDsoftware maintains a pointer to the most recent entry in the externalcommunication device event log.

The CD software provides memory space for storing the contents of theimplantable device event log and the ability to display those events onan ‘implantable device clinical history’ screen. The event code for themost recently logged implantable device event is initially displayed onthe screen. The CD software displays older entries in the implantabledevice event log when the down arrow is pressed and newer entries in theimplantable device event log when the up arrow is pressed. The CDsoftware ignores up key presses when the external communication deviceis displaying the most recent entry in the implantable device event logand down key presses when the external communication device isdisplaying the oldest entry in the implantable device event log. The CDsoftware maintains a pointer to the most recent entry in the implantabledevice Event Log. The CD software updates its implantable device eventlog to match the event log in the implantable device during a link andwhen executing the read implantable device data functionality.

The CD software provides memory space for storing entries to theimplantable device battery voltage log and the ability to display thoseentries on an implantable device voltage history screen. The CD softwareinitially displays the most recently logged loaded and unloadedimplantable device battery voltages on this screen. The CD softwaredisplays the older entries in this log when the down arrow is pressedand newer entries in this log when the up arrow is pressed. The CDsoftware ignores the pressing of the up key when the most recent entryin the log is being displayed and the down key when the oldest entry inthe log is displayed.

The external communication device maintains a pointer to the most recententry in the implantable device battery voltage log. The CD softwareupdates this log to match the battery voltage log in the implantabledevice during a link and when executing the read implantable device datafeature.

The CD software provides for a predefined number (e.g. 3 in the presentembodiment) of separately programmable sets of basal rates. Each set, orprofile, consists of a predefined number (e.g. up to 48 in the presentembodiment) of basal rates, one for each of a predefined set of timeslots (e.g. each half-hour of the day in the present embodiment). Theprofile rates are programmed by setting a start time and a rate. The CDsoftware provides a basal rate screen that allows the user to view thebasal rate that is currently being delivered. When there is no temporarybasal rate active (the temporary basal duration is zero), the CDsoftware displays the currently active basal profile along with itsnumber. When a temporary basal rate is active, the active profile numberis replaced with “OFF”.

The CD software displays the set profile rate screen showing profile 1when act is pressed when the ‘basal rate’ screen is displayed. when theact key is pressed from the set profile rate screen, the CD softwaredisplays the set profile start time screen. The minimum value forscrolling the start time is one half-hour after the start time of theprevious profile. When a profile start time is programmed with a starttime prior to that of one or more previously defined entries andsubsequent start times are cleared (e.g. set to dashes in the presentembodiment). Basal profile setting is complete when the rate for aprofile starting at 11:30 pm is set. Alternatively, basal profilesetting is completed when the user presses the act key for a profilestart time that is dashes. When profiles in the active pattern arechanged, the CD software prepares and sends a set profile basal ratesmessage to the implantable device.

The CD software allows up to 3 delivery patterns to be separatelyprogrammed with up to 48 rates each and the patterns to be stored in theexternal communication device. Any one of the patterns may be set activeat any time. The CD software allows the Selection of the active basaldelivery pattern from the set basal delivery pattern screen. When thebasal delivery pattern is set (i.e. made active) that pattern becomesaccessible on the ‘profile basal rate’ screen and a set profile basalrates message is prepared and transmitted to the implantable device.

The temporary basal rate is a basal rate that when programmed, will runin lieu of the basal profile rate. The temporary basal rate runs for theamount of time specified by the temporary basal duration. The CDsoftware enables setting of the temporary basal rate using the settemporary basal rate screen. When the temporary basal rate and durationare set, the CD software prepares and sends a set temporary basal ratemessage to the implantable device. When a temporary basal delivery is inprogress, the CD software causes the remaining temporary basal rateduration to be displayed on the temporary basal rate screen. When thereis no temporary basal rate delivery in progress, the CD software causesdashes to be displayed as the amount and duration of the temporary basalrate. When a temporary basal rate is set with a duration that is zero,any temporary basal rate in progress is canceled. When programming atemporary basal rate when a temporary basal rate is in progress, the CDsoftware sets the default duration to the time remaining on the ratethat is in progress rounded down to the nearest half-hour. The CDsoftware increases the duration by one half-hour when the up key ispressed and decreases the amount by one half-hour when down key ispressed. The CD software locks out the set temporary basal rate screenduring a diagnostic rate delivery and priming bolus delivery.

The CD software maintains a log of personal events. The CD softwareallows personal events to be set from a personal events screen. The CDsoftware updates the log with a time and event type after the usercompletes the personal event data entry sequence. The personal eventsscreen is not displayed when a personal events enable parameter is setto OFF. When the personal events screen is displayed, the most recentpersonal event is displayed. When the down key is pressed, the CDsoftware displays the previous personal event in the log and when the Upkey is pressed, the CD software displays the next personal event in thelog. The CD software ignores presses of the Down key when the oldestpersonal event is being displayed and ignores the Up key when the newestpersonal event is being displayed.

Automatic Off is set from the ‘set automatic off ’ screen. When theautomatic off duration is set the CD software prepares and sends a setautomatic off telemetry message to the implantable device. When theautomatic off interval is programmed to dashes, the CD software disablesthe feature. The CD software maintains a timer that indicates the amountof time remaining in the automatic off interval. When telemetryresponses from the implantable device are received, and the response isnot the interrogate response, the CD software resets the timer to theautomatic off interval. The CD software decrements the time in theautomatic off interval timer every minute. When the amount of time inthe automatic off interval is five minutes (indicating that theImplantable Device will alarm in 5 minutes), the CD software reports an“automatic off alarm” alarm.

The CD software maintains the time and the date. The CD software enablesthe time and the date to be set from the ‘time and date’ screen. WhenACT is pressed, the ‘set time’ screen is displayed. When the ‘set time’screen is displayed, the CD software allows the user to change the hoursand the minutes. When act is pressed and the minutes are displayed, theCD software displays the set date screen. When the date and the time areset by the user, the CD software prepares and sends out a set currenttime telemetry message to the implantable device. In the presentembodiment, though the external communication device has directknowledge of date and changes in date that may occur, this directknowledge is not used in determining, among other thing, how to setdaily totals. In alternative embodiments, this direct knowledge may beused for this purpose; however, in the present embodiment the followinganalysis is performed by the CD software and associated conclusionsmade: (1) If the new hour is less than the current hour (measured on a24 hour clock), and the new hour subtracted from the current hour isgreater than or equal to 12, new day processing takes place, (2) If thenew hour is greater than the current hour and the current hoursubtracted from the new hour is greater than or equal to 12, previousday processing takes place, and (3) If the new hour and current hour arenot separated by more than 12 hours the day is considered to remainunchanged. When new day processing occurs, the CD software updates thedaily totals as is normally carried out at midnight. When previous dayprocessing occurs, the CD software moves the daily total data logpointer to the previous day and adds current daily total values to thoseof the previous day.

An hourly maximum amount is provided for by the CD software. The hourlymaximum is the amount of insulin that may be delivered with boluses inone hour. If a higher amount is programmed, the CD software reports anerror. In the present embodiment, the hourly maximum amount is not ahard limit but one that may be bypassed if desired by the patient. Ineffect, the hourly maximum amount provides a warning to the patient sothat the patient will not unintentionally deliver a large amount ofinsulin within a single 60-minute period. In the present embodiment,after clearing the warning, a window of predefined length (e.g. 10minutes) is opened so that an additional bolus of up to the single bolusmaximum amount (i.e. bolus maximum) may be delivered without triggeringthe hourly maximum amount error. In the present embodiment the hourlymaximum amount is set to a predetermined multiple of the single bolusmaximum amount (e.g. 2.5 times). In alternative embodiments, the timeperiod of the maximum may be specified to a larger or shorter amountand/or the amount of the maximum may be set in a different way.

Each time a bolus is programmed, the CD software computes the amount ofbolus delivery that occurred during the previous 60 minutes. If theamount delivered summed with the programmed amount is greater than 2½times the bolus maximum, the CD software reports an “hourly maximumexceeded” alarm and the CD software does not transmit a telemetrymessage to the implantable device to initiate the bolus. When the“hourly maximum exceeded” alarm is cleared the CD software sets aten-minute time period in which CD software will not test for the“hourly maximum exceeded” alarm. The CD software resumes testing for the“hourly maximum exceeded” alarm after the ten-minute time periodelapses.

In other alternative embodiments, instead of basing the Hourly Maximumtesting on amounts actually delivered in the last 60 minutes, thetesting may be based on amounts programmed during the last 60 minutes.Also in alternative embodiments, an estimated timing of delivery for theamount(s) programmed may be factored into the calculations beforeconcluding that the hourly maximum will actually be exceeded, especiallywhen the amount programmed for delivery includes an extended bolus.

The CD software allows a basal rate maximum to be defined and then usesthis maximum value in limiting the basal rates that can be programmedfor delivery during any one period of time. In the present embodiment,the CD software inhibits the user from programming basal profiles ortemporary basal rates that are greater than the value of the basal ratemaximum. When the basal rate maximum is changed, the CD softwareprepares and sends the implantable device a set maximums Message. The CDsoftware inhibits a maximum basal rate from being programmed that is setto a value lower than a programmed basal rate, including profile basalrates, both active and inactive, and the temporary basal rate.

The CD software sets the medication remaining parameter to the refillamount when a response to a “set refill amount and alarm thresholds”message is received. The CD software subtracts the daily total values(not taken from the amounts displayed but instead derived from thenumber of pump strokes executed) from the “remaining medication”parameter once per day at midnight.

The CD software performs a self-test and initiates the implantabledevice self-test through telemetry. The external communication deviceself-test is initiated from the external communication device self-testscreen. When the external communication device self-test is initiated,the CD software sends an Initiate Self-Test telemetry message to theimplantable device so that it may be tested as well. When the CDsoftware receives a valid response to the initiate self-test telemetrymessage, the CD software indicates to the user that the ImplantableDevice has passed the self-test. If the external communication devicedoes not receive a response to the initiate self-test telemetry message,the CD software indicates that the implantable device has failed theself-test. The external communication device sends the implantabledevice a read self-test status message when the external communicationdevice wants to know the results of the test.

When the external communication device self-test is initiated, the CDsoftware displays the ‘screen operation verification’ screen, an alerttone is emitted, the vibrator is enabled for a predefined period of time(e.g. 3 seconds), the CD software computes a CRC of the code area ininternal RAM and compares the computed value to the CRC stored in theSEEPROM, the CD software computes a CRC of the code area in external RAMand compares the computed value to the CRC stored in the SEEPROM, andthe CD software illuminates the Backlight for a predefined period oftime (e.g. four seconds). If either of these CRC comparisons do notproduce a match, the CD software causes the external communicationdevice to reset. When the CD software has completed the self-testsequence, the CD software indicates that the external communicationdevice has passed the self-test (assuming it has). It is up to the userto confirm whether the vibrator operated and whether the display wasilluminated. In other embodiments, appropriate transducers and circuitrymay be used to automatically ascertain the functionality of variouscomponents such as those noted above.

The external communication device alarm type is set from the alarmsscreen, in conjunction with the audio feedback mode. audio and vibrationalarms are set by the ‘alarms’ screen. When the ‘alarms’ screen isdisplayed and the act key is pressed, the CD software displays theexternal communication device alarm type screen. When the alarm typescreen is displayed and the act key is pressed, the CD software displaysthe ‘audio feedback mode’ screen.

The CD software stores the alarm type parameter in the externalcommunication device memory but when the parameter is changed, it alsotransmits a set external communication device data block message(containing the updated alarm type parameter) to the implantable devicefor storage in the external communication device data block.

The CD software allows the audio feedback mode to be set from the alarmsscreen, in conjunction with the external communication device alarmtype. audio feedback mode is enabled and disabled from the set audiofeedback mode screen. When the audio feedback status parameter is set toON the CD software sends the implantable device the set audio feedbackmode message enabling audio feedback mode. When the audio feedbackstatus parameter is set to OFF the CD software sends the implantabledevice the set audio feedback mode telemetry message disabling audiofeedback mode.

The CD software causes the external communication device to storage modeif there is no keyboard activity and there have been no telemetrypackets received for seven days. The external communication device exitsstorage mode if a key is pressed or the batteries are removed andreplaced. When the external communication device is in storage mode, thescreen is disabled and the telemetry hardware is disabled, time ismaintained (but not displayed) and memory is retained but all otherfunctions become unavailable.

The pump refill process is initiated from the ‘pump refill’ screen.pressing act on the pump refill screen causes the ‘set extracted amount’screen to be displayed. Pressing ACT on the ‘set extracted amount’screen causes the ‘set refill amount’ screen to be displayed. Pressingact on the ‘set refill amount’ screen causes the ‘Set Concentration’screen to be displayed. Pressing ACT on the ‘set concentration’ screeninitiates the CD software to calculate the delivery accuracy. When theCD software computes the delivery accuracy to be a negative number, itdisplays the value as positive number along with the words“Under-Delivery”. When the cd software computes the delivery accuracy tobe a positive number, the value is displayed along with the words“over-delivery”. When the extracted amount is dashes, the extractedamount is logged as zero and this event is logged in the system eventlog. The accuracy is displayed as dashes. When the CD softwaredetermines that the extracted amount is more than the previous refillamount, the CD software logs a system event and displays the accuracy asdashes. When the CD software determines that the extracted amount equalsthe previous refill amount, the CD software logs a system event anddisplays the accuracy as dashes.

Changing the insulin concentration is part of the refill screensequence. When insulin concentration is changed on the ‘setconcentration’ screen, the CD software resets all profile basal ratesand the temporary basal rate to factory default values. When the basalprofiles are cleared, the CD software sends the implantable device a setbasal rates message and a set insulin concentration message. When theinsulin concentration is changed, the CD software recomputes the currentbasal rate maximum and bolus maximum and sends the implantable device aset maximums message.

The priming bolus screen is found on the supervisor menu. The CDsoftware locks out the priming bolus screen unless the pump is in stopmode. Priming the pump is initiated from the priming bolus screen. Whenthe user presses the act key on the ‘priming bolus’ screen, the CDsoftware displays the confirm priming bolus screen. When the userselects ‘yes’ and presses the act key on the ‘confirm priming bolus’screen, the CD software displays the reconfirm priming bolus screen.When the user presses the ACT key on the ‘reconfirm priming bolus’screen, the cd software sends a set delivery mode message to theimplantable device with the mode set to indicate priming bolus, and thepriming bolus amount set to a predefined value (such as 650 pumpstrokes).

The diagnostic rate screen is on the supervisor menu. It is used toperform diagnostic procedures on the pumping mechanism by setting veryhigh rates. Normally, the reservoir is not filled with insulin when thisfeature is used. The diagnostic rate screen is locked out unless thepump is in stop mode. diagnostic rate is initiated on the ‘diagnosticrate’ screen. When the user presses the act key on the ‘diagnostic rate’screen, the CD software displays the set diagnostic rate Screen. Whenthe user presses the act key on the set diagnostic rate screen, the cdsoftware displays the confirm diagnostic rate screen. When the userselects ‘yes’ and presses the act key on the confirm diagnostic ratescreen, the CD software displays the reconfirm diagnostic rate screen.When the user presses the act key on the reconfirm diagnostic ratescreen, the CD software prepares and sends a set delivery mode messageto the implantable device with the mode set to indicate diagnostic rate,and the diagnostic rate amount equal to the amount set on the ‘setdiagnostic rate’ screen. While the diagnostic rate is in progress, theCD software displays a message on the ‘time and message’ screen toindicate that the diagnostic rate is in progress.

The maximum lock feature is a safety feature accessible from thesupervisor menu. This feature enables and disables the patient's abilityto change the delivery maximums. The maximum lock feature is accessibleon the ‘lock bolus and basal maximums’ screen. When the user presses actfrom this screen, the set lock screen is displayed. When the userpresses act on the set lock screen, the CD software sends a set maximumsmessage to the implantable device. When the locked maximum statusparameter is on, the CD software ignores the act key when it is pressedwhile the max bolus screen is displayed. When the locked maximum statusparameter is on, the CD software ignores the act key when it is pressedwhile the max basal rate screen is displayed.

The read implantable device data feature synchronizes the externalcommunication device and the implantable device. The read implantabledevice data feature is accessible from the read implantable device datascreen. When the user presses act on this screen, the CD softwareinitiates the read implantable device data process. The read implantabledevice data process includes reading the Implantable device data logpointers and reading all of the data necessary to make the data logs inthe external communication device mirror the data logs in theimplantable device.

Setting the personal ID is initiated on the personal ID screen. When actis pressed on the personal ID screen, the CD software displays the “setpersonal id character 1” screen. As there are 32 characters availablefor use as the personal ID in this embodiment, 32 screens are suppliedfor entry of the personal ID. When ACT is pressed on the final characterof the personal ID, the CD software sends a “set personal id message” tothe implantable device.

The external communication device contains an image of the implantabledevice software in one of its SEEPROMs. The image includes instructionsto perform all of the telemetry transactions necessary to download thesoftware, including for example, an interrogate message, a link message,a reset message, an interrogate message, a link message, download startmessage & data, one or more download continue messages and data, and abootstrap message. The SEEPROM includes code and data for both the mainand the monitor processors on the implantable device. Downloadingimplantable device software is initiated on the “download implantabledevice software” screen. When the user presses the act key on the“download implantable device software” screen, the CD software displaysthe “confirm download implantable device software” screen. When the userselects ‘yes’ and presses the act key on this screen, the CD softwaredisplays the re-confirm download implantable device software screen.When the user presses the ACT key on this screen, the CD softwareinitiates the software download. The CD software reads the SEEPROM anduses the size and the data, in formulating telemetry packets to send tothe implantable device. If appropriate message responses are received bythe CD software, it continues sending packets until the data read fromthe SEEPROM indicates that there is no more data. If errors are detectedduring the download process, the CD software displays the download errorscreen.

Stop mode is a mode where the implantable device is programmed to stopall insulin delivery. The CD software limits accessibility to onlysupervisor menu screens when the pump is in stop mode. stop mode isenabled from the “stop pump” screen. When stop mode is entered, the CDsoftware prepares and transmits a telemetry message to the implantabledevice to set the delivery mode to stop mode. When stop mode is entered,the CD software displays the alarm screen with “pump stopped” alarmactive. When the “pump stopped” alarm condition is cleared, the CDsoftware sets prepares and sends a telemetry message to the implantabledevice to set the delivery mode to normal mode and also updates thebolus history log to indicate the amount of the latest bolus that wasdelivered.

The CD software provides single command ability to set parameter valuesin the implantable device to their factory default values. Thiscapability is produced from the “initialize to factory defaults” screen.Several telemetry commands are used to initialize the implantable deviceto factory defaults successfully. When the choice is confirmed to resetthe parameters, the CD software sends the telemetry messages indicatedin the following table to the implantable device to set the parametersto their factory default values: Telemetry Messages to Initialize toFactory Defaults Set Current Time Set Automatic Off Set ExternalCommunication Device Data Block Set Maximums Set Audio Feedback Mode SetPersonal ID Set Temp Basal Rate Set Basal Profile Rates Set DeliveryMode

The CD software provides a one command process for initializing theexternal communication device to implantable device. After completingthis sequence, the external communication device is configured to matchthe implantable device settings with the exception of the basal profileswhich are set to factory defaults in the implantable device and theexternal communication device. The Initialize external communicationdevice to implantable device process is initiated from the initializeexternal communication device to implantable device screen. When the ACTkey is pressed and the ‘initialize external communication device toimplantable device’ screen is being displayed, the CD software sends theimplantable device an interrogate message. When the response to theinterrogate telemetry message is received, the CD software displays the‘confirm implantable device serial number’ Screen. This screen containsa message that gives the user the choice to confirm or reject thedisplayed personal ID. The user may choose “yes” or “no” to confirm orreject and abort the initialization process. The CD software sets the“no” choice as the default. When the ‘no’ choice is confirmed, theexternal communication device attempts to add the telemetry ID from theinterrogate response message to the exclusion list. If the exclusionlist is full, the CD software reports an “exclusion list full” alarm. Ifthe exclusion list is not full, the CD software sends out anotherinterrogate message, in hopes of getting the correct implantable deviceto respond. The rejection process may be repeated multiple times if alarge number of implantable devices are in the vicinity. When the ‘yes’choice is confirmed, the CD software sends the telemetry messages to theimplantable device as indicated in the table below. Telemetry Messagesto Initialize the External Communication Device to Implantable DeviceInterrogate Link External Communication Device to Implantable DeviceRead Stroke Volume Read Lifetime Total Delivered Read Audio FeedbackMode Read Insulin Concentration Read Automatic Off Read ImplantableDevice Data Log Pointers Read Refill Counter Read Maximums Read ExternalCommunication Device Data Block Read Memory Set Temp Basal Rate SetBasal Profile Rates Set Delivery Mode

The stroke volume received in the read stroke volume response isrange-checked by the CD software to ensure that it is a valid value. Ifthe stroke volume is not within range, and “invalid stroke volume” alarmis reported, and the CD software will not initialize the externalcommunication device to the implantable device. If valid, the CDsoftware stores the stroke volume as received and once more in itscomplimented form.

The insulin concentration received in the read concentration response isalso range checked by the CD software to ensure that it is a validvalue. If the insulin concentration is not within the range, the CDsoftware reports an “invalid stroke volume” alarm and the CD softwarewill not initialize the external communication device to the implantabledevice. If valid, the CD software stores the insulin concentration asreceived and once more in its complimented form.

With the set delivery mode message, the CD software sets the deliverymode to suspend. With the set temporary basal rate and the set basalprofile rates messages, the CD software sets the implantable devicebasal rates, including the profiles and temp basal rates to the factorydefault values.

During programming of the external communication device, if there is noactive alarm and no buttons are pressed, the external communicationdevice will return to the ‘time and message’ screen after a predefinedperiod of inactivity. When an alarm is in the process of being cleared,the CD software returns the external communication device to the “timeand alarm” screen. The time-out (i.e. predefined period of inactivity)is dependent upon the last key that was pressed, if telemetry occurred,and if an alarm was beeping. In the present embodiment, severaldifferent time out periods are used: (1) The time-out is 4 seconds aftertelemetry occurs; (2) 15 seconds after an interrogate; (3) 15 secondsafter audio bolus beeping; (4) 7 seconds after a sel key is pressed; (5)15 seconds after all other keys are pressed, except for when the downkey is pressed to activate the backlight; and (6) 4 seconds after theactivation of the backlight.

The CD software provides a set of functions that are only accessiblewith a supervisor password. In order for the user to access thesupervisor menu, the user must enter a supervisor password on thepassword screen. When a predefined group of keys are pressedsimultaneously (e.g. the two arrow keys), for a predefined number ofseconds (e.g. 3-5 seconds), from one or more selected screens (e.g. thetime alarm & sel screen, or the pump setup screen) the password screenis displayed. When the user is presented with the password screen, theuser enters a selected number of parameters (e.g. four parametersdefined as password entry 1, password entry 2, password entry 3, andpassword entry 4). The CD software presents one parameter at a time forentry. When the act key is pressed, subsequent password entry parametersmay be entered. when “act” is pressed after specifying password entry 4,the CD software compares password entry 1-4 parameters to password 1-4parameters. If the four values match, the CD software displays the‘supervisor menu’ screen. If the values do not match, the CD softwarecompares password entry 1-4 parameters to the factory passwordparameters 1-4. If the four values are within a predefined amount ofeach other (e.g. less than or equal to 24 apart), the CD softwaredisplays the supervisor menu screen. If the values do not match, the CDsoftware displays the time and message screen. The following tablespresent a listing of the various screen names along with a briefdescription of them. The Main Menu contains the following screens MainMenu Screens Screen Description Time This is the screen that displaysthe current time and the icons. Time and This screen will be displayedwhen there are messages such as Message bolus delivery in progress andtemporary basal rate in progress. Bolus History This is the screen thatshows the boluses that have been delivered. A new bolus may be startedfrom this screen. Suspend Pump This is the screen where the user canstop (clinically speaking) insulin delivery. Basal Rate This is thescreen where the basal profiles may be reviewed and programmed.Temporary Basal Rate This is the screen where a temporary basal rate maybe programmed or canceled. Personal Events This screen is where the usercan record the incidence of events (when enabled) such as exercise andmeals for later review. Note that this screen will not be in the MainMenu unless it is enabled in the Setup II menu. History Menu This is amenu (described below) that shows historical insulin deliveryinformation. Pump Setup This is the menu where the pump setup optionsare located.

The History Menu contains the following screens: History Menu ScreensScreen Description Read This screen is where the user can Synchronizethe Implantable Implantable Device data and the external communicationdevice data. Device Data Medication This screen shows how muchmedication is remaining in the pump Remaining reservoir. Daily TotalsThis screen shows the total amount of insulin delivered for the mostrecent 90 days. Exit History This screen exits the History Menu andreturns to the Main Menu. External This screen shows the externalcommunication device Event Log Communication entries. Device ClinicalHistory Implantable This screen shows the Implantable Device Event Logentries. Device Clinical History Implantable This screen shows theImplantable Device Battery Voltage Log Device Voltage entries. History

The Pump Setup Menu contains the following screens: Pump Setup MenuScreens Screen Description Time and Date This is the screen where theuser sets the time and the date. Automatic Off This is the screen wherethe user sets and clears the automatic off duration. Alarms This is thescreen where the user sets the alarm type (audio high, audio low, orvibrator) and where the user sets audio feed back mode. Self-Test Thisis the screen where the user initiates a self-test for the externalcommunication device and the Implantable Device. Basal Delivery This isthe screen where one of the three basal profile delivery Patternpatterns is selected. Initialize This is where the externalcommunication device and the External Implantable Device are “married”.This must be carried out before Communication an external communicationdevice and an Implantable Device can Device to communicate. Implant PumpSetup II This is where the Pump II menu can be entered. Exit Setup Thisscreen exits the Pump Setup Menu and returns to the Main Menu.

The Pump Setup II Menu contains the following screens: Pump Setup IIMenu Screens Screen Description Audio Bolus This is where the audiobolus feature is enabled and disabled. Variable Bolus This is where theability to choose a bolus type on the bolus setting screen is enabledand disabled. Maximum Bolus This is where the maximum bolus amount isset. Maximum Basal This is where the maximum basal rate is set. RateTime display This is where the time display can be set to either 12-houror 24- format hour clock. Personal Events This is where the personalevents feature is enabled and disabled. Exit to Pump This screen exitsPump Setup II and enters Pump Setup I menu. Setup Exit Setup This screenexits the Pump Setup II menu and returns to the Main Menu.

The Supervisor Menu contains the following screens: Supervisor MenuScreens Screen Description Refill This is where the user enters theamount of medication put into the pump. This is used for the low andempty reservoir alarms. Priming Bolus This is where a priming bolus thatis designed to remove air from the catheter is programmed. DiagnosticRate This where the diagnostic rate is programmed. Bolus and Basal Thisis where the ability for the user to change Maximum Lock maximums in thePump Setup II Menu is enabled and disabled. Personal ID This is wherethe 32 character personal ID is set. Initialize to This feature programspump parameters to the Factory Defaults factory defaults. Download PumpThis is where the pump software can be downloaded. Software. Stop PumpThis feature stops and resumes all pumping. Set Supervisor This is wherethe password for the Supervisor Password Menu is set. Exit SupervisorThis screen exits the Supervisor Menu and returns Menu to the Main Menu.

Any field that is displayed and that may be changed over the productlifetime is identified as a parameter field. To clarify parameterdefinition, parameters can be thought of as being subdivided intonumeric parameters and option parameters. The numeric parameter willgenerally be a number. The definition for numeric parameters includes aminimum value and a maximum value and a unit of how the parameter ismeasured. For all parameters, the defaults values are shown. Numericparameters also include a step value that indicates how scrolling willincrement and decrement when the parameter can be changed by the user.Numeric parameters may show dashes when they are disabled. This isindicated by the term ‘dashes’. Option parameters will generally be aset of options that the user scrolls through when the parameter is set.Option Parameters are shown with all the available choices and thedefault.

The factory default is the value or option that the parameter will beset to when the external communication device is shipped from thefactory as a new product. The operating default is the value or optionthat the parameter will be set to when the external communication devicehas been initialized properly to an Implantable Device, and the user hasinteracted with the parameter. PART 1 - External Communication DeviceParameter Summary Factory Delta Parameter Default Operating DefaultUnits Value Accuracy “%” will be displayed. “Under Status Delivery” willbe displayed if Delivery Accuracy is negative; otherwise “Over Delivery”will be displayed. Audio 0.4 Previously programmed value. Units 0.4Bolus Increment Audio OFF Previously programmed value. Bolus StatusAudio OFF Previously programmed value. Feedback Status Auto-Off DISABLEDPreviously programmed value. Hours 1 Duration Basal Rate Units TotalBolus Dashes Last Bolus Amount Units Amount Bolus NORMAL NORMAL DeliveryType Bolus Blank. Dependent upon pump status. Status The text PROGRAMMEDwill be displayed at any time the bolus on the screen has not beenconfirmed as being delivered. If the bolus has been delivered thissection of screen will be blank. Bolus Time Dashes Time & Date of lastbolus dependent on & Date Time Format and Date Format parametersettings. Daily Total Dashes Previously programmed value. Units BasalAmount Daily Total Dashes Previously programmed value. Units BolusAmount Daily Total Dashes Previously programmed value. Month and DateDay Day 1 Previously programmed value. 1 day Delivery [100 × (EstimatedDelivery − Amount Percent Accuracy Delivered)/Amount Delivered], whereAmount Delivered is [Previous Refill Amount − Extracted Amount] andEstimated Delivery is ((1.04 g/mL) × Units Delivered/ InsulinConcentration) Delivery A Previously programmed value. PatternDiagnostic 10 10 Units/hour 5 Rate Event Time Current Current Time &Date Dependent on & Date Time & Time Format Date Event Type MEAL MEALExtended Dashes Dashes Units 0.2 Bolus Amount Extended 30 30 minutesHours:minutes 30 Bolus minutes minutes Duration Extracted 0.1 0.1 Grams0.1 Amount Factory Operating (24 * Month * 32 + 24 * Day + Hour)Password Default (Note that January is 0, 1-4 February is 1, etc) Hour 0Previously programmed value. Dependent on 1 hour Time Format parametersetting. Immediate Dashes Dashes Units 0.2 Bolus Amount Insulin U-400Previously programmed value. Concentration Implantable 2-byte 2-bytefrom Telemetry Device SW from version Telemetry Locked OFF Previouslyprogrammed value. Maximums Status Maximum 0.2 Previously programmedvalue. Units/hour 0.1 Basal Rate Maximum 10 Previously programmed value.Units 0.2 Bolus Medication 0 Previously programmed value. UnitsRemaining Minutes 0 minutes Previously programmed value. Dependent on 1minute Time Format parameter setting. Month JAN Previously programmedvalue. Password Y Previously programmed value. Character 1 Password IPreviously programmed value. Character 2 Password Q Previouslyprogrammed value. Character 3 Password 8 Previously programmed value.Character 4 Password 0 0 Entry Character 1-4 Personal OFF Previouslyprogrammed value Event Status Personal ID 0 Previously programmed value.Character 1-32 ECD HIGH Previously programmed value. Alarm Type CD2-byte 2-byte stored value. software stored Version value. Priming[((Pump [((Pump Volume) + (Catheter Units Bolus Volume) + (CatheterVolume)) × (Insulin Volume)) ×(Insulin Concentration)] Concentration)]Profile Dashes Previously programmed value. u/h 0.1 Basal Rate AmountProfile Previous Previously programmed value. Dependent on 30 Basal Ratestart time Time Format minutes Start Time plus 30 parameter minutessetting. Refill 0.1 0.1 Grams 0.1 Amount Temporary Dashes Dashesunits/hour 0.1 Basal Rate Amount Temporary Dashes Dashes Hours:minutes30 Basal Rate minutes Duration Time 12 Previously programmed value.Format HOUR Variable OFF Previously programmed value. Bolus Status Year2000 Previously programmed value. 1 year

PART 2 - External Communication Device Parameter Summary InterfaceInterface Number of Parameter Minimum Maximum Options Records AccuracyStatus Audio Bolus 0.4 0.8 Increment Audio Bolus Status ON or OFF AudioFeedback ON or OFF Status Auto-Off Duration DISABLE 16 D and then 1Basal Rate Total Bolus Amount 512 Bolus Delivery Type NORMAL, DUAL, ORSQUARE Bolus Status Bolus Time & Date 512 Daily Total Basal 120 AmountDaily Total Bolus 120 Amount Daily Total Date 120 Day 1 31 DeliveryAccuracy 0 100 Delivery Pattern A, B, or C Diagnostic Rate 10 240 for U-400, 300 for U-500 Event Time & Date 512 Event Type MEAL, SNACK, 512SICK, EXERCISE, A, B, C. Extended Bolus Dashes and Dependent on Amountthen 0.2 U Maximum Bolus parameter Extended Bolus 30 minutes 4 hoursDuration Extracted Amount Dashes and 25 then 0.1 U Factory Password 1-4Hour 0 11:00 PM Immediate Bolus Dashes and Dependent on Amount then 0.2U Maximum Bolus parameter Insulin U-400, or U-500 ConcentrationImplantable Device SW version Locked Maximums ON or OFF Status MaximumBasal 0.2 35 Rate Maximum Bolus 0 25 Medication Remaining Minutes 0minutes 59 minutes Month JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP,OCT, NOV, DEC Password Character 1 number 0 letter Z Password Character2 number 0 letter Z Password Character 3 number 0 letter Z PasswordCharacter 4 number 0 letter Z Password Entry number 0 letter Z Character1-4 Personal Event ON or OFF Status Personal ID number 0 letter ZCharacter 1-32 External HIGH, LOW, or Communication VIBRATE Device AlarmType CD software Version Priming Bolus Profile Basal Rate Dashes anddependent on 48 per Amount then 0.1 Maximum Delivery Basal Rate Patternparameter Profile Basal Rate previous 11:30 PM 48 per Start Time starttime Delivery plus 30 Pattern minutes (except if it is Profile 1, whichalways starts at 12:00 am) Refill Amount 0.1 25 Temporary Basal Dashesand Dependent on Rate Amount then 0.1 Maximum Basal Rate parameterTemporary Basal Dashes and 24 hours Rate Duration then 30 minutes TimeFormat 12 HOUR or 24 HOUR Variable Bolus ON or OFF Status Year 1999 2050

The external communication device may use its IrDA port to communicatewith other secondary external devices, such as a desktop personalcomputers. The external communication device may communicate with twoclasses of secondary devices: (1) devices for extracting informationfrom the communication device for providing primarily health carerelated analysis for use by the patient or physician, i.e. a clinicianstation, and (2) devices for extracting information from and writinginformation to the communication device for system related diagnosticsand problem solving, i.e. diagnostic station.

The clinician station may be a desktop computer running a programdesigned to monitor and display diagnostic information provided by theexternal communication device and an implantable device for a healthcare professional. The clinician station type external device cannotwrite data to the external communication device or the implantabledevice.

The diagnostic station may be a desktop computer running a programdesigned to aid in the diagnosis of system problems throughcommunication with the implantable device and the external communicationdevice. The diagnostic station has the capability to write data to theimplantable device and to the external communication device.

A full-duplex link between, the external communication device and ansecond external device such as the clinician station is provided throughthe serial communication port. This port provides transmit and receivelines that support infrared LEDs for establishing functional connectionsto external devices. The transmit and receive lines also support RS232connections to external devices.

Messages are initiated by the second external device. The receivingdevice allows a predefined time before concluding the transmission hasended. If this time is exceeded before a complete message is received,the receiving device responds with a “no acknowledge” message. Thereceiver expects the next byte to be the first byte of a message.

The external communication device maintains a low power state bydisabling some of the UART circuitry. The second external devicetransmits a “wake-up” message in order to enable the externalcommunication device receiver. When the external communication device isin the UART low power state and a byte is received, the externalcommunication device enables all UART capabilities appropriate forcommunication with an external device. When the external communicationdevice UART is idle for 10 seconds it enters the low-power state. Allmessages except for a wake-up and listen message follow a format similarto that noted above for an RF telemetry message.

For safety reasons the external communication device recognizes twodistinct communication channels using the IR port: the clinician channeland the diagnostic channel. The clinician station software uses aclinician channel to communicate to the external communication device.The messages that are available for each channel type are different. Theclinician channel messages do not modify external communication deviceor implantable device memory but diagnostic channel messages can. Aspecific channel closes when the “channel close” message is received orwhen the interval between messages exceeds a predefined channel time outinterval. Each channel is closed upon system start-up and remains closeda “channel open” message is received for that specific channel.

While the above description has provided various teachings concerninghow the communication device may handle various RF telemetry operations,IR communication operations, alarm notifications, and other functionalactivities, many other such operations are definable. These otheroperations may be defined in manners that are analogous to the teachingspresented above or in ways that are consistent with those teachings anddo not lead to communication ambiguity or other potential mishandling ofmedical device operation.

The above embodiment and its alternatives provide numerous enhancementsin the electronic control of the medical device. These improvementsprovide more functional, reliable, safe, user friendly, convenienceoperation of an implantable medical device and more generically of anambulatory medical device.

While the above embodiment has primarily been concerned with animplantable infusion pump that dispenses insulin using a piston type(i.e. pulsatile) pump mechanism, the electronic control featuresdisclosed herein may be used in other ambulatory devices such asimplantable pacemakers, defibrillators, other implantable tissuestimulators, implantable physiologic sensors such as electrochemicaloxygen sensors, peroxide sensors, or enzymatic sensors such as glucosesensors, externally carried infusion pumps, implantable infusion pumpsthat use other pumping mechanisms or simply used excess pressure andcontrolled flow elements to infuse various medications and drugs such asanalgesics, drugs for treating AIDS, drugs for treating psychologicaldisorders and the like. For example, the features presented above may beused with an external infusion pump that may or may not have a built indisplay and keypad but is equipped with a telemetry system that cancommunicate with a physically separated communication device so that thepump need not be accessed in order to provide commands to it and receivedata from it.

In these various alternatives, the physical, electronic, and programmedfeatures of the communication device and implantable device may havedifferent components and features than presented above for theimplantable pump system so that their desired medical functionality andsafety requirements are achieved and such that appropriate control andfeedback is provided between the medical device and its communicationdevice.

In other alternative embodiments the medical device may include twomedical devices such as an implantable pump and an implantable sensor.The pump may dispense a drug whose physiological impact on the body(e.g. analgesic impact) is ascertained by the sensor or alternativelythe sensor may supply a physiological reading that indicates a need forinfusion of the drug. The pump may operate in a closed loop manner withthe sensor or it may operate in an open loop manner where the patient isrequired to interpret sensor output information and is required to issueappropriate infusion commands to the pump. For example, in the case of adiabetic patient, the drug may be insulin and the sensor may detectglucose level.

In other alternative embodiments two medical devices may be implantedadjacent one another or at an extended distance from one another. If notplaced in physical contact with one another, a lead may be used toprovide power conduction from one device to the other and also be usedto conduct communication signals between the devices. Alternatively,each device may include at least one telemetry system that allows directcommunication between each or allows indirect communication to occur viathe external communication device or other external device. Each devicemay be supplied with its own power supply. Depending on thecommunication requirements each device may use two way communication(i.e. both outbound and inbound communication) or allow only one waycommunication (i.e. outbound communication or possibly inboundcommunication).

In other alternatives, both the medical device and the communicationdevice may be external devices (e.g. an external pump and an external RFtelemetry based communication device). In still further alternatives, afirst type of medical device may be implanted (e.g. an infusion pump ora sensor) while a second medical device may be external (e.g. theopposite of a sensor or an infusion pump). Where at least one of themedical devices is external, it may also function as the communicationdevice for the other medical device in which case it may possess adisplay for providing information to the patient and a keypad forallowing entry of commands for issuance to the implantable device aswell as for direct use by itself. Even if at least one of the medicaldevices is external, it may be inconvenient to access that device wheninformation is needed or commands must be given, as such an external,non-medical communication device may be supplied that has informationoutput (e.g. display) capabilities and input (e.g. keypad) capabilities.If a separate communication device is provided, the external medicaldevice may or may not have display and input capabilities.

The telemetry features presented above may be used with various forms ofdistant communication (e.g. between the implantable device and otherexternal devices or between the external communication device and otherexternal devices). For example communication may occur via variouselectromagnetic links like IR, optical links, longer or shorterwavelength RF, audio links, ultrasonic links, acoustic links, inductivelinks, and the like. Various telemetry systems may be used. Telemetrysystems may be of the analog type, digital type, or mixed.

In other embodiments two independent processors may be used that operatefrom a single timing chain. In these alternatives, it is preferable thatat least one of the timing signals (e.g. one of the lower frequencytimers) be monitored by an independently timed watchdog circuit toreduce the risk of timing problems going undetected.

In still additional embodiments, an implantable glucose sensor may beused in conjunction with an implantable insulin pump to provide feedbackto the patient or physician on the effectiveness of the insulin deliverysystem. The patient could use the feedback to assist in making insulindelivery decisions in an open loop manner. Alternatively, the operationof the pump could be tied to the sensor output in a more or less closedloop manner to give a more automated character to system operation.Insulin may be infused without any user intervention, withoutpre-delivery information, and even without direct post deliveryfeedback. In a less automated closed loop system, drug infusionrecommendations could be derived by the system and presented to the userbefore delivery or the system could require user acknowledgment prior toproceeding with delivery for amounts or rates exceed a predefined limit.The implantable sensor may have its own power supply or may receivepower from the control circuitry provided within the pump housingthrough a physical lead that connects them. Power may be suppliedthrough one or more independent leads or alternatively may betransferred over one or more data lines through the communicationsignals themselves. Communication may be exchanged in various waysincluding, for example, via galvanic leads, RF telemetry, fiber optics,and the like, and may be of digital, analog, or combined form. Thesensor system may include a plurality of sensor elements which mightallow continued glucose data to be supplied even though some portion ofthe sensors stop operating, lose calibration or produce questionablereadings. The most preferred sensors would include electronic processingcapability in the form of an integrated circuit mounted in or forming apart of a housing for the sensor. This configuration has the advantageof allowing digital communications between the physical sensor and anyseparated electronic control module.

Further teachings concerning implantable sensors and implantable sensorsystems are found in a number of patents issued to D. A. Gough,including (1) U.S. Pat. No. 4,484,987, entitled “Method And MembraneApplicable To Implantable Sensor”; (2) U.S. Pat. No. 4,627,906, entitled“Electrochemical Sensor Having Improved Stability”; (3) U.S. Pat. No.4,671,288, entitled “Electrochemical Cell Sensor For ContinuousShort-Term Use In Tissues And Blood”; (4) U.S. Pat. No. 4,703,756,entitled “Complete Glucose Monitoring System With An ImplantableTelemetered Sensor Module”; and (5) U.S. Pat. No. 4,781,798, entitled“Transparent Multi-Oxygen Sensor Array And Method Of Using Same”. Eachof these patents is incorporated herein by reference as if set forth infull.

Still further teachings concerning implantable sensors and sensorsystems are found in a number of patents issued to J. H. Schulman, etal., including (1) U.S. Pat. No. 5,497,772, entitled “Glucose MonitoringSystem”; (2) U.S. Pat. No. 5,651,767, entitled “Replaceable CatheterSystem for Physiological Sensors, Stimulating Electrodes and/orImplantable Fluid Delivery Systems”; (3) U.S. Pat. No. 5,750,926,entitled “Hermetically Sealed Electrical Feedthrough For Use WithImplantable Electronic Devices”; (4) U.S. Pat. No. 6,043,437, entitled“Alumina Insulation for Coating Implantable Components and OtherMicrominiature Devices”; (5) U.S. Pat. No. 6,088,608, entitled“Implantable Sensor and Integrity Test Therefor”; and (6) U.S. Pat. No.6,119,028, entitled “Implantable Enzyme-Based Monitoring Systems HavingImproved Longevity Due to Improved Exterior Surfaces”. Each of thesepatents is incorporated herein by reference as if set forth in full.

Additional further teachings concerning implantable sensors and sensorsystems are found in (1) U.S. Pat. No. 5,917,346, issued to J. C. Gord,et al., and entitled “Low power current-to-frequency converter”; (2)U.S. Pat. No. 5,999,848, issued to J. C. Gord, and entitled “DaisyChainable Sensors for Implantation in Living Tissue”; (3) U.S. Pat. No.5,999,849, issued to L. D. Canfield, et al., and entitled “Low PowerRectifier Circuit for Implantable Medical Devices”; and (4) U.S. Pat.No. 6,081,736, issued to M. S. Colvin, et al., and entitled “ImplantableEnzyme-Based Monitoring Systems Adaptedfor Long Term Use”. Each of thesepatents is incorporated herein by reference as if set forth in full.

Further teachings concerning implantable infusion pumps are found in anumber of patents by R. E. Fischell, including (1) U.S. Pat. No.4,373,527, entitled “Implantable, Programmable Medication InfusionSystem”; (2) U.S. Pat. No. 4,494,950, entitled “Infusion DeviceIntendedfor Implantation in a Living Body”; (3) U.S. Pat. No. 4,525,165,entitled “Fluid Handling System for Medication Infusion System”; (4)U.S. Pat. No. 4,573,994, entitled “Refillable Medication InfusionApparatus”; (5) U.S. Pat. No. 4,594,058, entitled “Single ValveDiaphragm Pump with Decreased Sensitivity to Ambient Conditions”; (6)U.S. Pat. No. 4,619,653, entitled “Apparatus For Detecting At Least OnePredetermined Condition And Providing An Informational Signal InResponse Thereto In A Medication Infusion System”; (7) U.S. Pat. No.4,661,097, entitled “Methodfor Clearing a Gas Bubble From a PositiveDisplacement Pump Contained Within a Fluid Dispensing System”; (8) U.S.Pat. No. 4,731,051, entitled “Programmable Control Means for ProvidingSafe and Controlled Medication Infusion”; and (9) U.S. Pat. No.4,784,645, entitled, “Apparatus For Detecting A Condition Of AMedication Infusion System And Providing An Informational Signal InResponse Thereto”. Each of these patents is incorporated herein byreference as if set forth in full.

Still further teachings concerning infusion pumps are found in a numberof patents by Franetzki, including (1) U.S. Pat. No. 4,191,181, entitled“Apparatus For Infusion of Liquids”, (2) U.S. Pat. No. 4,217,894,entitled “Apparatus for Supplying Medication to the Human or AnimalBody”; (3) U.S. Pat. No. 4,270,532, entitled “Device for thePre-programmable Infusion of Liquids”; (4) U.S. Pat. No. 4,282,872,entitled “Device for the Pre-programmable Infusion of Liquids”, U.S.Pat. No. 4,373,527, entitled “Implantable, Programmable MedicationInfusion System”; (5) U.S. Pat. No. 4,511,355, entitled “Plural ModuleMedication Delivery System”, (6) U.S. Pat. No. 4,559,037, entitled“Device for the Pre-programmable Infusion of Liquids”; (7) U.S. Pat. No.4,776,842, entitled “Device for the Administration of Medications”. Eachof these patents is incorporated herein by reference as if set forth infull.

Teachings concerning tissue stimulators are found in a number of patentsby J. H. Schulman, including (1) U.S. Pat. No. 5,193,539, entitled“Implantable microstimulator”; (2) U.S. Pat. No. 5,193,540; entitled“Structure and Method of Manufacture of an Implantable Microstimulator”;and (3) U.S. Pat. No. 5,358,514, entitled “Implantable Microdevices withSelfAttaching Electrodes”. Further teachings are also found in (1) U.S.Pat. No. 5,957,958, by Loeb et al., entitled “Implantable nerve ormuscle stimulator e.g. a cochlear prosthesis”, in (2) U.S. Pat. No.5,571,148, by G. E. Loeb, et al., entitled “Implantable MultichannelStimulator”; and in (3) PCT Publication No. WO 00/74751, by A. E. Mann,and entitled “Method and Apparatus for Infusing Liquids Using a ChemicalReaction in an Implanted Infusion Device”. Each of these publications isincorporated herein by reference as if set forth in full.

The control of an implantable sensor could be provided through thefunctionality of one or both Processor ICs. One Processor IC couldsupply power and/or control signals to the sensor(s) and receive databack from the sensor, while the other processor could monitor theactivity to ensure that sensor activity meets certain predefinedguidelines.

In other embodiments, the External Communication Device of the firstembodiment could be functionally linked to an external glucose sensorsystem such as the continuous glucose monitoring system (CGMS) offeredby Minimed Inc. of Northridge, Calif. The link may be established, forexample, through a physical lead or by RF telemetry.

In other embodiments other implantable, or external, sensor systems thatmeasure something other than glucose could also be functionally coupledto the implantable device either to receive power and/or to providedata. Other such sensors might include oxygen sensors, peroxide sensors,pulse rate sensors, temperature sensors, accelerometers, and the like.

In still other alternative embodiments, the electronic control system ofthe first embodiment could be configured to control one or moreimplantable sensors or electrical stimulators with or without infusionfunctionality incorporated into the implantable device.

Further embodiments will be apparent to those of skill in the art uponreview of the disclosure provided herein. Still further embodiments maybe derived from the teachings set forth explicitly herein in combinationwith the teachings found in the various patent applications.

While the description herein sets forth particular embodiments, it isbelieved that those of skill in the art will recognize many variationsto the presented embodiments based on the teachings herein, as such itis believed that many additional modifications may be made withoutdeparting from the spirit of the teachings herein. The accompanyingclaims are intended to cover such modifications as would fall within thetrue scope and spirit of the present invention.

The disclosed embodiments are therefore to be considered as illustrativeand not necessarily restrictive, the scope of the invention beingindicated by the appended claims, rather than the foregoing description,and all changes which come within the meaning and range of equivalencyof the claims are therefore intended to be embraced therein.

1. A method comprising: activating wireless telemetry circuitry in anexternal communication device to communicate with an implantable medicaldevice; and disabling a backlight of a display in the externalcommunication device during activation of the telemetry circuitry toreduce electrical interference.
 2. The method of claim 1, furthercomprising disabling the backlight in response to a telemetry quiet modesignal.
 3. The method of claim 1, further comprising enabling thebacklight when the telemetry is not activated.
 4. The method of claim 1,wherein the external communication device includes an internal antenna,and the telemetry circuitry receives signals from the implantablemedical device via the internal antenna during activation of thetelemetry circuitry.
 5. The method of claim 1, wherein the externalcommunication device includes an internal antenna, and the telemetrycircuitry transmits signals to the implantable medical device via theinternal antenna during activation of the telemetry circuitry.
 6. Themethod of claim 1, wherein the implantable medical device includes animplantable electrical stimulator.
 7. The method of claim 1, wherein theimplantable medical device includes an implantable pump.
 8. The methodof claim 1, wherein the display includes a liquid crystal display. 9.The method of claim 1, wherein the backlight includes anelectroluminescent backlight.
 10. The method of claim 1, wherein theexternal communication device is capable of being hand-held and isbattery-powered.
 11. An external communication device for an implantablemedical device, the external communication device comprising: a devicehousing; an antenna coupled to the housing; wireless telemetrycircuitry, within the housing, that communicates with the implantablemedical device via the antenna; a display, within the housing, thatpresents information; a backlight that illuminates the display; andcontrol circuitry that disables the backlight during activation of thetelemetry circuitry to reduce electrical interference.
 12. The externalcommunication device of claim 11, wherein the control circuitry disablesthe backlight in response to a telemetry quiet mode signal.
 13. Theexternal communication device of claim 11, wherein the control circuitryenables the backlight when the telemetry is not activated.
 14. Theexternal communication device of claim 11, wherein the antenna isinternally mounted within the housing, and the telemetry circuitryreceives signals from the implantable medical device via the internalantenna during activation of the telemetry circuitry.
 15. The externalcommunication device of claim 11, wherein the antenna is internallymounted within the housing, and the telemetry circuitry transmitssignals from the implantable medical device via the internal antennaduring activation of the telemetry circuitry.
 16. The externalcommunication device of claim 11, wherein the implantable medical deviceincludes an implantable electrical stimulator, and the externalcommunication device includes processing circuitry that programs theimplantable electrical stimulator via the telemetry circuitry.
 17. Theexternal communication device of claim 11, wherein the implantablemedical device includes an implantable pump, and the externalcommunication device includes processing circuitry that programs theimplantable pump via the telemetry circuitry.
 18. The externalcommunication device of claim 11, wherein the display includes a liquidcrystal display.
 19. The external communication device of claim 11,wherein the backlight includes an electroluminescent backlight.
 20. Theexternal communication device of claim 11, wherein the externalcommunication device is capable of being hand-held and isbattery-powered.
 21. A method comprising: activating wireless telemetrycircuitry in an external communication device to communicate with animplantable medical device, wherein the external communication deviceincludes an internal antenna, and the telemetry circuitry receivessignals from the implantable medical device via the internal antennaduring activation of the telemetry circuitry; disabling anelectroluminescent backlight of a liquid crystal display in the externalcommunication device during activation of the telemetry circuitry toreduce electrical interference in response to a telemetry quiet modesignal; and enabling the backlight when the telemetry is not activated.